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1. Domain Analysis Every software falls into some domain category The expert people in the domain can be a great help to analyze general and specific requirements Brainstorming An informal debate is held among various stakeholders and all their inputs are recorded for further requirements analysis 30 Software Engineering Tutorial Prototyping Prototyping is building user interface without adding detail functionality for user to interpret the features of intended software product It helps giving better idea of requirements If there is no software installed at client s end for developer s reference and the client is not aware of its own requirements the developer creates a prototype based on initially mentioned requirements The prototype is Shown to the client and the feedback is noted The client feedback serves as an input for requirement gathering Observation Team of experts visit the client s organization or workplace They observe the actual working of the existing installed systems They observe the workflow at the client s end and how execution problems are dealt The team itself draws some conclusions which aid to form requirements expected from the software Software Requirements Characteristics Gathering software requirements is the foundation of the entire software development project Hence they must be clear correct and well defined A complete Software Requirement Specifications must be e Clear e
2. e Technological changes environmental changes business competition Risk Management Process There are following activities involved in risk management process e Identification Make note of all possible risks which may occur in the project e Categorize Categorize known risks into high medium and low risk intensity as per their possible impact on the project e Manage Analyze the probability of occurrence of risks at various phases Make plan to avoid or face risks Attempt to minimize their side effects e Monitor Closely monitor the potential risks and their early symptoms Also monitor the effective steps taken to mitigate or avoid them Project Execution and Monitoring In this phase the tasks described in project plans are executed according to their schedules Execution needs monitoring in order to check whether everything is going according to the plan Monitoring is observing to check the probability of risk and taking measures to address the risk or report the status of various tasks These measures include 21 Software Engineering Tutorial e Activity Monitoring All activities scheduled within some task can be monitored on day to day basis When all activities in a task are completed it is considered as complete e Status Reports The reports contain status of activities and tasks completed within a given time frame generally a week Status can be marked as finished pending or work in progress
3. Q zl J 2 Te Software engineering is an engineering branch associated with development of software product using well defined scientific principles methods and procedures The outcome of software engineering is an efficient and reliable software product Definitions IEEE defines software engineering as Software Engineering Tutorial 1 The application of a systematic disciplined quantifiable approach to the development operation and maintenance of software that is the application of engineering to software 2 The study of approaches as in the above statement Fritz Bauer a German computer scientist defines software engineering as Software engineering is the establishment and use of sound engineering principles in order to obtain economically software that is reliable and work efficiently on real machines Software Evolution The process of developing a software product using software engineering principles and methods is referred to as Software Evolution This includes the initial development of software and its maintenance and updates till desired software product is developed which satisfies the expected requirements Change Request System Release Software Impact Analysis Evolution system update Release Planning EE NEER EER Evolution starts from the requirement gathering process After which developers create a prototype of the intended software and show it to the users to get their
4. Software Engineering Tutorial But at times it is impossible to design a software that works on the target machines 79 Software Engineering Tutorial Software Testing Overview Software Testing is evaluation of the software against reguirements gathered from users and system specifications Testing is conducted at the phase level in software development life cycle or at module level in program code Software testing comprises of Validation and Verification Software Validation Validation is process of examining whether or not the software satisfies the user requirements It is carried out at the end of the SDLC If the software matches requirements for which it was made it is validated e Validation ensures the product under development is as per the user requirements e Validation answers the question Are we developing the product which attempts all that user needs from this software e Validation emphasizes on user requirements Software Verification Verification is the process of confirming if the software is meeting the business requirements and is developed adhering to the proper specifications and methodologies e Verification ensures the product being developed is according to design specifications e Verification answers the question Are we developing this product by firmly following all design specifications d e Verifications concentrates on the design and system specifications Target of the tes
5. feedback at the early stage of the software product development The users Suggest changes on which several consecutive updates and maintenance keep on changing too This process changes to the original software till the desired software is accomplished Even after the user has the desired software in hand the advancing technology and the changing requirements force the software product to change accordingly Re creating software from scratch and to go one on one with the requirement is Software Engineering Tutorial not feasible The only feasible and economical solution is to update the existing software so that it matches the latest requirements Software Evolution Laws Lehman has given laws for software evolution He divided the software into three different categories 1 Static type S type This is a software which works strictly according to defined specifications and solutions The solution and the method to achieve it both are immediately understood before coding The s type software is least subjected to changes hence this is the simplest of all For example calculator program for mathematical computation 2 Practical type P type This is a software with a collection of procedures This is defined by exactly what procedures can do In this software the specifications can be described but the solution is not obviously instant For example gaming software 3 Embedded type E type This software works closely as t
6. les OE EE EE AA OE EE OE AA 23 CTI SOT AE EE EE EE EE EE EE EE 23 ERNEIEREN 24 Ee EA AE EE IE OE ON OE OE OE ER OE N ORE OE ENE 24 PERI C O ege 25 POS OUNCES IIS ee de OE N EE EE N IE EE N EA OE EE EO N 25 GTEC OL GED sales OE ER OE EE EE OE OE EO OE 26 SOFTWARE REGUIREMENTS ii eie ads si ee deele 27 REQUIREMENT ENGINEERING tege 27 REQUIREMENT ENGINEERING PROCESS esse esse see e se ees sees ee ee ee ee ee ee ee ee ee ee ee ee ee ee Ee ee Ee ee Ee ee ee ee ee ee ee ee ee 27 sole ig SOIC OE N AE OE OE OE OE OO EA 27 Reduiement Eet sees Side ve Ee ER GR ED E ge Oe Ge io Ge Ee 28 Software Requirement Specification SRS ees see ee ee ee ee ee ee ee RE ee ee ee ee ee 28 Software Requirement ValidatiON ees ee ee ee ee ee ee ee ee ee ee ee Ee 28 PEGEL 29 REOUIREMENT ELICITATION Re let 29 Vitae OE NEE N EE NE N EE mere 30 aa ORR ER N ER EA ER EE E A 30 QUESTIONO EO EE N OE EN DT N OE OR OE EE EE N N EE EE A 30 ge dele RE TE EE EE OE N EO EIE N 30 PON ig eN NOY OER EE OE EE OO NA ENE ON 30 gelek ae sug I AT EE OE EO NE OE EE NEE OE OE EE EG 30 o OVP AO N E E OR EE EE Oe ee 31 Ged 0 O AR EO NE ROER ER EO DR N RE EE EO EN 31 SOFTWARE REQUIREMENTS CHARACTERISTICS esse see see se ee see se ee see see see se ee ede ese ee ee ee ee de ee AA Re ee ee 31 SOFWARE EE EEN 31 ele ee Re 32 Non Functional Requirements ees see ee ee ee ee ee ee ee ee ee ee ee 32 USER INTERFACE SEELEN Ge Gee ee ee Ee ee ee be Ge EG Ge ee oe 33 SOFTW
7. objects Every entity has some attributes associated to it and has some methods to perform on the attributes 55 Software Engineering Tutorial Classes A class is a generalized description of an object An object is an instance of a class Class defines all the attributes which an object can have and methods which defines the functionality of the object In the solution design attributes are stored as variables and functionalities are defined by means of methods or procedures Encapsulation In OOD the attributes data variables and methods operation on the data are bundled together is called encapsulation Encapsulation not only bundles important information of an object together but also restricts access of the data and methods from the outside world This is called information hiding Inheritance OOD allows similar classes to stack up in hierarchical manner where the lower or sub classes can import implement and re use allowed variables and methods from their immediate super classes This property of OOD is known as inheritance This makes it easier to define specific class and to create generalized classes from specific ones Polymorphism OOD languages provide a mechanism where methods performing similar tasks but vary in arguments can be assigned same name This is called polymorphism which allows a single interface performing tasks for different types Depending upon how the function is invoked respective portion o
8. product The user contacts the service provider and tries to negotiate the terms submits the request to the service providing organization in writing Requirement Gathering This step onwards the software development team works to carry on the project The team holds discussions with various stakeholders from problem domain and tries to bring out as much information as possible on their requirements The requirements are contemplated and segregated into user requirements system requirements and functional requirements The requirements are collected using a number of practices as given Software Engineering Tutorial e studying the existing or obsolete system and software e conducting interviews of users and developers e referring to the database or e collecting answers from the questionnaires Feasibility Study After requirement gathering the team comes up with a rough plan of software process At this step the team analyzes if a software can be designed to fulfill all requirements of the user and if there is any possibility of software being no more useful It is also analyzed if the project is financially practically and technologically feasible for the organization to take up There are many algorithms available which help the developers to conclude the feasibility of a software project System Analysis At this step the developers decide a roadmap of their plan and try to bring up the best software model suitable for the
9. user s end Early discovery of errors and their remedy is the key to reliable software Integration Software may need to be integrated with the libraries databases and other program s This stage of SDLC is involved in the integration of software with outer world entities Implementation This means installing the software on user machines At times software needs post installation configurations at user end Software is tested for portability and adaptability and integration related issues are solved during implementation Operation and Maintenance This phase confirms the software operation in terms of more efficiency and less errors If required the users are trained on or aided with the documentation on how to operate the software and how to keep the software operational The software is maintained timely by updating the code according to the changes taking place in user end environment or technology This phase may face challenges from hidden bugs and real world unidentified problems Software Development Paradigm The software development paradigm helps a developer to select a strategy to develop the software A software development paradigm has its own set of tools methods and procedures which are expressed clearly and defines software development life cycle A few of software development paradigms or process models are defined as follows Waterfall Model Waterfall model is the simplest model of software development par
10. 2 o Days Critical Path Analysis This tools is useful in recognizing interdependent tasks in the project It also helps to find out the shortest path or critical path to complete the project successfully Like PERT diagram each event is allotted a specific time frame This tool shows dependency of event assuming an event can proceed to next only if the previous one is completed The events are arranged according to their earliest possible start time Path between start and end node is critical path which cannot be further reduced and all events require to be executed in same order Fa 26 Software Engineering Tutorial Software Requirements The software requirements are description of features and functionalities of the target system Requirements convey the expectations of users from the software product The requirements can be obvious or hidden known or unknown expected or unexpected from client s point of view Requirement Engineering The process to gather the software requirements from client analyze and document them is known as requirement engineering The goal of requirement engineering is to develop and maintain sophisticated and descriptive System Requirements Specification document Requirement Engineering Process It is a four step process which includes e Feasibility Study e Requirement Gathering e Software Requirement Specification e Software Requirement Validation Let us see the pro
11. Average 10 7 Complex 15 10 The table above yields raw Function Points These function points are adjusted according to the environment complexity System is described using fourteen different characteristics These characteristics factors are then rated from 0 to 5 as mentioned below Data communications Distributed processing Performance objectives Operation configuration load Transaction rate Online data entry End user efficiency Online update Complex processing logic Re usability Installation ease Operational ease Multiple sites Desire to facilitate changes No influence 72 Software Engineering Tutorial Incidental Moderate Average Significant Essential All ratings are then summed up as N The value of N ranges from O to 70 14 types of characteristics x 5 types of ratings It is used to calculate Complexity Adjustment Factors CAF using the following formulae CAF 0 65 0 01N Then Delivered Function Points FP CAF x Raw FP This FP can then be used in various metrics such as Cost FP Quality Errors FP Productivity FP person month 73 Software Engineering Tutorial Software Implementation In this chapter we will study about programming methods documentation and challenges in software implementation Structured Programming In the process of coding the lines of code keep multiplying thus size of the software increases Gradually it become
12. Correct e Consistent e Coherent e Comprehensible e Modifiable e Verifiable e Prioritized e Unambiguous e Traceable e Credible source Software Requirements We should try to understand what sort of requirements may arise in the requirement elicitation phase and what kinds of requirement are expected from the software system 31 Software Engineering Tutorial Broadly software requirements should be categorized in two categories Functional Requirements Requirements which are related to functional aspect of software fall into this category They define functions and functionality within and from the software system EXAMPLES e Search option given to user to search from various invoices e User should be able to mail any report to management e Users can be divided into groups and groups can be given separate rights e Should comply business rules and administrative functions e Software is developed keeping downward compatibility intact Non Functional Requirements Requirements which are not related to functional aspect of software fall into this category They are implicit or expected characteristics of software which users make assumption of Non functional requirements include e Security e Logging e Storage e Configuration e Performance e Cost e Interoperability e Flexibility e Disaster recovery e Accessibility Requirements are categorized logically as e Must Have Software cannot be said
13. DALA FOC KEER EE EE EE EE EE OE N EE N ors 53 SOFTWARE DESIGN STRATEGIES TT 54 STRUCTURED DESIGN MR RE EE OE OE OE 54 FUNCTION ORIENTED RT EC 55 DOS OF OCS EH 55 OBJECT ORIENTED DESIGN ee 55 BE ed le 56 EEGEN 57 TOO DOW DES IN RE EE OE OO ER EE OE ER OE OE AE N 57 Ere ee se CSIC I OE OE EE EE IE EE N EE NE 57 SOFTWARE USER INTERFACE DESIGN eege ne ode dee Se se wise se oe ee eo ee oi de ee Gee see Add de Gee 58 COMMAND LINE INTERFACE e D UE 58 EE 59 GRAPHICAL USER INTERFACE EE 60 CUTE EE RR EE AEE EE AE 60 Application specific GUI componentS sees ee ee ee ee ee ee ee ee ee ee ee Ee 61 EREECHEN 62 GUMHMPELEMENTA NON Tee 64 EE 64 USER INTERFACE GOLDEN RULES sesse ss oes ske ee dees oe ees vie bo N is ENN EAn AENEAN TAREE ee bee ene ed geg 64 SOFTWARE DESIGN COMPLEXITY eege dE dE 67 FIAESTEAD S COMPLEXITY MEASDRES Gee oe see Do ee Bee ke ee io ee EE EE Ee Ge ie N EE De ie 67 CYCLOMATIC COMPLEXITY MEASURES Ee 68 FONCTION POINT erra T 70 sep el 4 6 ebe 70 ape OU de EA EE EE EE OE EE N OR OE 71 LOJON ENO Fl CS osse RE GE en Ee ae Ge N EG ee ee ee AEE 71 Eternal EE 71 EKO et E 71 SOFTWARE IMPLEMENTATION ugeet getest deed see de sede ee oe so eed sed oe Ged be oe ee dee ek Ge de se De ee 74 STRUCTURED PROGR TE 74 FICTIONAL ROG RAIN Oe 75 Meter HOCH d E 76 COA IS NES de oe ee oto ER oe ee ee oe oe oe 76 SOFTWARE DOCUMENTATION E 77 SOFTWARE IMPLEMENTATION CHALLENGES esse see sees see se ee see se ee see see ese se ee see es
14. Here both Structured English and Pseudo Code tries to mitigate that understanding gap Structured English uses plain English words in structured programming paradigm It is not the ultimate code but a kind of description what is required to code and how to code it The following are some tokens of structured programming IF THEN ELSE DOT WATERS UNTE Analyst uses the same variable and data name which are stored in Data Dictionary making it much simpler to write and understand the code Example We take the same example of Customer Authentication in the online shopping environment This procedure to authenticate customer can be written in Structured English as Enter Customer_Name SEEK Customer Name in Customer Name DB file IF Customer Name found THEN Call procedure USER PASSWORD AUTHENTICATE ELSE PRINT error message Call procedure NEW CUSTOMER REOUEST ENDIF 47 Software Engineering Tutorial The code written in Structured English is more like day to day spoken English It can not be implemented directly as a code of software Structured English is independent of programming language Pseudo Code Pseudo code is written more close to programming language It may be considered as augmented programming language full of comments and descriptions Pseudo code avoids variable declaration but they are written using some actual programming language s constructs like C Fortran Pascal etc Pseudo code contains more pr
15. If there are any ambiguities If they are complete If they can be demonstrated Requirement Elicitation Process Requirement elicitation process can be depicted using the folloiwng diagram Requirement Requirement Hi Negotiation amp Requirement Gathering Organisation gj Discussion Specification Requirements gathering The developers discuss with the client and end users and know their expectations from the software Organizing Requirements The developers prioritize and arrange the requirements in order of importance urgency and convenience Negotiation amp discussion If requirements are ambiguous or there are some conflicts in requirements of various stakeholders it is then negotiated and discussed with the stakeholders Requirements may then be prioritized and reasonably compromised The requirements come from various stakeholders To remove the ambiguity and conflicts they are discussed for clarity and correctness Unrealistic requirements are compromised reasonably Documentation All formal and informal functional and non functional requirements are documented and made available for next phase processing Requirement Elicitation Techniques Requirements Elicitation is the process to find out the requirements for an intended software system by communicating with client end users system users and others who have a stake in the software system development There are various ways to discover requirem
16. Prograni RESUCTUNNO E 92 FORWOTO E NOE e EE 92 COMPONENT REUSABILIT AE N N EA OE N RE 93 EE 93 REUSE Mee RE EE ER OE EE N 93 SOFTWARE CASE TOOLS OVERVIEW is oie siese ees ee ee de ee Ke GE eg ee een ee De ee de ee Ge EG be gee ide 100 CA ES cea gee ec EE N EE EE EE EE EE 100 COMPONENTS OF CASE TOOLS es Ge DEE EE Oe GE ee ee ei ene ee 100 SCOPE OF CASE Ee 101 VOC del od dele E 101 PROCESS MOO NI FONG RE N O EE RE EE 101 Project Management EE 102 Documentation TOONS AA EE N ELE IE EE E OE AE E 102 ANG ee EE 102 BO ea kie eo OE AE ETE EE EE RE OE N N ee ee 102 Configuration Management Tools 102 Change Control TOOL OE N AE EE OE N EI ER N 103 Progamming TOON tee oe Ge E rE E RE ei ee RE De EE Se Ee 103 POPOL MG ee 103 Wep Development EEN 103 Quality Assurance N gele OE EO EE kirsis dduru eii ikerin NE N 103 Ma itepanEe EE 103 Software Engineering Tutorial Software Overview Let us understand what Software Engineering stands for The term is made of two words software and engineering Software is more than just a program code A program is an executable code which serves some computational purpose Software is considered to be collection of executable programming code associated libraries and documentations Software when made for a specific requirement is called software product Engineering on the other hand is all about developing products using well defined scientific principles and methods
17. Software Design Basics Software design is a process to transform user reduirements into some suitable form which helps the programmer in software coding and implementation For assessing user requirements an SRS Software Requirement Specification document is created whereas for coding and implementation there is a need of more specific and detailed requirements in software terms The output of this process can directly be used into implementation in programming languages Software design is the first step in SDLC Software Design Life Cycle which moves the concentration from problem domain to solution domain It tries to specify how to fulfill the requirements mentioned in SRS Software Design Levels Software design yields three levels of results e Architectural Design The architectural design is the highest abstract version of the system It identifies the software as a system with many components interacting with each other At this level the designers get the idea of proposed solution domain e High level Design The high level design breaks the single entity multiple component concept of architectural design into less abstracted view of sub systems and modules and depicts their interaction with each other High level design focuses on how the system along with all of its components can be implemented in forms of modules It recognizes modular structure of each sub system and their relation and interaction among each
18. Software Engineering It means development and maintenance of software projects with help of various automated software tools CASE Tools CASE tools are set of software application programs which are used to automate SDLC activities CASE tools are used by software project managers analysts and engineers to develop software system There are number of CASE tools available to simplify various stages of Software Development Life Cycle such as Analysis tools Design tools Project management tools Database Management tools Documentation tools are to name a few Use of CASE tools accelerates the development of project to produce desired result and helps to uncover flaws before moving ahead with next stage in software development Components of CASE Tools CASE tools can be broadly divided into the following parts based on their use at a particular SDLC stage e Central Repository CASE tools require a central repository which can serve as a source of common integrated and consistent information Central repository is a central place of storage where product specifications requirement documents related reports and diagrams other useful information regarding management is stored Central repository also serves as data dictionary 100 Software Engineering Tutorial E HM D Analysis O P gt i Design 3 ae DD Impl tation S mpiemen DI i m A mMm Mag N Testing ai J gt UD m Maintenance e Upper Case
19. analyst after the requirements are collected from various stakeholders SRS defines how the intended software will interact with hardware external interfaces speed of operation response time of system portability of software across various platforms maintainability speed of recovery after crashing Security Quality Limitations etc The requirements received from client are written in natural language It is the responsibility of the system analyst to document the requirements in technical language so that they can be comprehended and used by the software development team SRS should come up with the following features e User Requirements are expressed in natural language e Technical requirements are expressed in structured language which is used inside the organization e Design description should be written in Pseudo code e Format of Forms and GUI screen prints e Conditional and mathematical notations for DFDs etc Software Requirement Validation After requirement specifications are developed the requirements mentioned in this document are validated User might ask for illegal impractical solution or experts may interpret the requirements inaccurately This results in huge increase 28 Software Engineering Tutorial in cost if not nipped in the bud Requirements can be checked against following conditions If they can be practically implemented If they are valid and as per functionality and domain of software
20. each iteration the management team can do work on risk management and prepare for the next iteration Because a cycle includes small portion of whole 11 Software Engineering Tutorial software process it is easier to manage the development process but it consumes more resources Spiral Model Spiral model is a combination of both iterative model and one of the SDLC model It can be seen as if you choose one SDLC model and combined it with cyclic process iterative model A ei Ss Alternate Objective Be Identification Evaluation Cumulative Cost a m ya e Te br e y as Next Phase 3 l Product Planning 3 Development Release i Oo ZA This model considers risk which often goes un noticed by most other models The model starts with determining objectives and constraints of the software at the start of one iteration Next phase is of prototyping the software This includes risk analysis Then one standard SDLC model is used to build the software In the fourth phase of the plan of next iteration is prepared V model The major drawback of waterfall model is we move to the next stage only when the previous one is finished and there was no chance to go back if something is 12 Software Engineering Tutorial found wrong in later stages V Model provides means of testing of software at each stage in reverse manner Requirement Acceptance Gathering Testing System AE Sys
21. etc e Milestones Checklist Every project is divided into multiple phases where major tasks are performed milestones based on the phases of SDLC This milestone checklist is prepared once every few weeks and reports the status of milestones Project Communication Management Effective communication plays vital role in the success of a project It bridges gaps between client and the organization among the team members as well as other stake holders in the project such as hardware suppliers Communication can be oral or written Communication management process may have the following steps e Planning This step includes the identifications of all the stakeholders in the project and the mode of communication among them It also considers if any additional communication facilities are required e Sharing After determining various aspects of planning manager focuses on sharing correct information with the correct person at the correct time This keeps every one involved in the project up to date with project progress and its status e Feedback Project managers use various measures and feedback mechanism and create status and performance reports This mechanism ensures that input from various stakeholders is coming to the project manager as their feedback e Closure At the end of each major event end of a phase of SDLC or end of the project itself administrative closure is formally announced to update every stakeholder by send
22. gopal staf sw r s 1 gopal staff rwe re re 1 gopal staff sw z s 8 l gopal staff sw r r 8 1 gopal staff sw z s 8 I gopal staff tw r r 1l gopal staff TWEE A gopal staff gw E g d 1 gopal staff sw r r 1 gopal staff rw r 2c 1 gopal staff sw s s i gopal staff zw r 2 1 gopal staff sw r r 1 gopal staff Pinaca lib gooalf Parameters id lib bash 80x24 Bell B 714 Jul 2 2013 476 Oct 24 09 20 15264 Jul 2 2013 annotations api jar utput 54142 Jul 2 2013 catalina ant ijar 134215 Jul 2 2013 catalina ha jar 257520 Jul 2 2013 catalina tribes jar 1581311 Jul 2 2013 catalina ar 1901636 Jul 2 2013 ec 4 2 2 jar 46085 Jul 2 2013 el api jar 123241 Jul 2 2013 jasper el jar 599428 Jul 2 2013 jasper jar 88690 Jul 2 2013 jsp api jar 177598 Jul 2 2013 servlet api jar 6873 Jul 2 2013 tomeat api jar 796527 Jul 2 2013 tomeat coyote jar 235411 Jul 2 2013 tomeat dbep jar 77364 Jul 2 2013 tomcat ilfn es jar 48693 Jul 2 2013 tomeat il8n fr jar 51678 Jul 2 2013 tomcat ilBn ja jar 124006 Jul 2 2013 tomcat jdbc jar 23201 Jul 2 2013 tomeat util jar Cursor Command Prompt A text based command line interface can have the following elements e Command Prompt It is text based notifier that is mostly shows the context in which the user is working It is generated by the software system e Cursor It is a small horizontal line or a vertical bar of the height of line to represe
23. high user and data load under various environment conditions Security amp Portability These tests are done when the software is meant to work on various platforms and accessed by number of persons Acceptance Testing When the software is ready to hand over to the customer it has to go through last phase of testing where it is tested for user interaction and response This is important because even if the software matches all user requirements and if user does not like the way it appears or works it may be rejected Alpha testing The team of developer themselves perform alpha testing by using the system as if it is being used in work environment They try to find out how user would react to some action in software and how the system should respond to inputs Beta testing After the software is tested internally it is handed over to the users to use it under their production environment only for testing purpose This is not as yet the delivered product Developers expect that users at this stage will bring minute problems which were skipped to attend Regression Testing Whenever a software product is updated with new code feature or functionality it is tested thoroughly to detect if there is any negative impact of the added code This is Known as regression testing Testing Documentation Testing documents are prepared at different stages 84 Software Engineering Tutorial Before Testing Testing starts with test ca
24. how well the software works in operations It can be measured on e Budget e Usability e Efficiency e Correctness e Functionality e Dependability e Security e Safety Transitional This aspect is important when the software is moved from one platform to another e Portability e Interoperability e Reusability e Adaptability Maintenance This aspect briefs about how well the software has the capabilities to maintain itself in the ever changing environment e Modularity e Maintainability e Flexibility e Scalability Software Engineering Tutorial In short Software engineering is a branch of computer science which uses well defined engineering concepts reguired to produce efficient durable scalable in budget and on time software products Software Engineering Tutorial Software Development Life Cycle Software Development Life Cycle SDLC for short is a well defined structured seguence of stages in software engineering to develop the intended software product SDLC Activities SDLC provides a series of steps to be followed to design and develop a software product efficiently SDLC framework includes the following steps Communication Requirement Gathering Feasibility Study System Analysis Software Design SDLC Coding Testing Integration Implementation Operations amp Maintenance Disposition Communication This is the first step where the user initiates the request for a desired software
25. in real time throughout the organization For example Creative Pro Office Trac Project Basecamp Documentation Tools Documentation in a software project starts prior to the software process goes throughout all phases of SDLC and after the completion of the project Documentation tools generate documents for technical users and end users Technical users are mostly in house professionals of the development team who refer to system manual reference manual training manual installation manuals etc The end user documents describe the functioning and how to of the system such as user manual For example Doxygen DrExplain Adobe RoboHelp for documentation Analysis Tools These tools help to gather requirements automatically check for any inconsistency inaccuracy in the diagrams data redundancies or erroneous omissions For example Accept 360 Accompa CaseComplete for requirement analysis Visible Analyst for total analysis Design Tools These tools help software designers to design the block structure of the software which may further be broken down in smaller modules using refinement techniques These tools provides detailing of each module and interconnections among modules For example Animated Software Design Configuration Management Tools An instance of software is released under one version Configuration Management tools deal with e Version and revision management e Baseline configuration management e Change c
26. information e User centric approach e Group based view settings Software System Analyst System analyst in an IT organization is a person who analyzes the requirement of proposed system and ensures that requirements are conceived and documented properly and acuurately Role of an analyst starts during Software Analysis Phase 33 Software Engineering Tutorial of SDLC It is the responsibility of analyst to make sure that the developed software meets the reguirements of the client System Analysts have the following responsibilities e Analyzing and understanding requirements of intended software e Understanding how the project will contribute to the organizational objectives e Identify sources of requirement e Validation of requirement e Develop and implement requirement management plan e Documentation of business technical process and product requirements e Coordination with clients to prioritize requirements and remove ambiguity e Finalizing acceptance criteria with client and other stakeholders Software Metrics and Measures Software Measures can be understood as a process of quantifying and symbolizing various attributes and aspects of software Software Metrics provide measures for various aspects of software process and software product Software measures are fundamental requirements of software engineering They not only help to control the software development process but also aid to keep the quality of ult
27. of screen They can be moved anywhere on the screen A window may contain another window of the same application called child window e Tabs If an application allows executing multiple instances of itself they appear on the screen as separate windows Tabbed Document Interface has come up to open multiple documents in the same window This interface 60 Software Engineering Tutorial also helps in viewing preference panel in application All modern web browsers use this feature Menu Menu is an array of standard commands grouped together and placed at a visible place usually top inside the application window The menu can be programmed to appear or hide on mouse clicks Icon An icon is small picture representing an associated application When these icons are clicked or double clicked the application window is opened Icon displays application and programs installed on a system in the form of Small pictures Cursor Interacting devices such as mouse touch pad digital pen are represented in GUI as cursors On screen cursor follows the instructions from hardware in almost real time Cursors are also named pointers in GUI systems They are used to select menus windows and other application features Application specific GUI components A GUI of an application contains one or more of the listed GUI elements Application Window Most application windows uses the constructs supplied by operating systems but many use their
28. operational without them e Should have Enhancing the functionality of software e Could have Software can still properly function with these requirements e Wish list These requirements do not map to any objectives of software 32 Software Engineering Tutorial While developing software Must have must be implemented Should have is a matter of debate with stakeholders and negation whereas Could have and Wish list can be kept for software updates User Interface requirements User Interface UI is an important part of any software or hardware or hybrid system A software is widely accepted if it is e easy to operate e quick in response e effectively handling operational errors e providing simple yet consistent user interface User acceptance majorly depends upon how user can use the software UI is the only way for users to perceive the system A well performing software system must also be equipped with attractive clear consistent and responsive user interface Otherwise the functionalities of software system can not be used in convenient way A system is said to be good if it provides means to use it efficiently User interface requirements are briefly mentioned below e Content presentation e Easy Navigation e Simple interface e Responsive e Consistent UI elements e Feedback mechanism e Default settings e Purposeful layout e Strategical use of color and texture e Provide help
29. other e Detailed Design Detailed design deals with the implementation part of what is seen as a system and its sub systems in the previous two designs It is more detailed towards modules and their implementations It defines logical structure of each module and their interfaces to communicate with other modules 91 Software Engineering Tutorial Modularization Modularization is a technique to divide a software system into multiple discrete and independent modules which are expected to be capable of carrying out task s independently These modules may work as basic constructs for the entire software Designers tend to design modules such that they can be executed and or compiled separately and independently Modular design unintentionally follows the rule of divide and conquer problem solving strategy this is because there are many other benefits attached with the modular design of a software Advantage of modularization e Smaller components are easier to maintain e Program can be divided based on functional aspects e Desired level of abstraction can be brought in the program e Components with high cohesion can be re used again e Concurrent execution can be made possible e Desired from security aspect Concurrency Back in time all software are meant to be executed sequentially By sequential execution we mean that the coded instruction will be executed one after another implying only one portion of program bein
30. other The lower the coupling the better the program There are five levels of coupling namely e Content coupling When a module can directly access or modify or refer to the content of another module it is called content level coupling e Common coupling When multiple modules have read and write access to some global data it is called common or global coupling e Control coupling Two modules are called control coupled if one of them decides the function of the other module or changes its flow of execution e Stamp coupling When multiple modules share common data structure and work on different part of it it is called stamp coupling e Data coupling Data coupling is when two modules interact with each other by means of passing data as parameter If a module passes data structure as parameter then the receiving module should use all its components Ideally no coupling is considered to be the best Design Verification The output of software design process is design documentation pseudo codes detailed logic diagrams process diagrams and detailed description of all functional or non functional requirements The next phase which is the implementation of software depends on all outputs mentioned above It is then becomes necessary to verify the output before proceeding to the next phase The early any mistake is detected the better it is or it might not be detected until testing of the product If the outputs of d
31. own customer created windows to contain the contents of application Dialogue Box It is a child window that contains message for the user and request for some action to be taken For Example Application generate a dialogue to get confirmation from user to delete a file NO Mapteg id ed Do you want to save the changes made to the document Untithied Your changes will Ge imt f you Cont save ther Save As Untitled txt Taga Where Desktop Don t Save Cancel Save Text Box Provides an area for user to type and enter text based data Buttons They imitate real life buttons and are used to submit inputs to the software 61 Software Engineering Tutorial Radio Buttons Time options s Digital Analog _ Display the time with seconds __ Flash the time separators _ Use a 24 hour clock d d Show AM PM At Check Box Show the day of the week W Show date Date options e Radio button Displays available options for selection Only one can be selected among all offered e Check box Functions similar to list box When an option is selected the box is marked as checked Multiple options represented by check boxes can be selected e List box Provides list of available items for selection More than one item can be selected First day of week G T E Monday Calendar Tuesday Wednesday Time forma ne Thursday i List sort order Friday Saturday f S
32. project System analysis includes understanding of software product limitations learning system related problems or changes to be done in existing systems beforehand identifying and addressing the impact of project on organization and personnel etc The project team analyzes the scope of the project and plans the schedule and resources accordingly Software Design Next step is to bring down whole knowledge of requirements and analysis on the desk and design the software product The inputs from users and information gathered in requirement gathering phase are the inputs of this step The output of this step comes in the form of two designs logical design and physical design Engineers produce meta data and data dictionaries logical diagrams data flow diagrams and in some cases pseudo codes Coding This step is also Known as programming phase The implementation of software design starts in terms of writing program code in the suitable programming language and developing error free executable programs efficiently Testing An estimate says that 50 of whole software development process should be tested Errors may ruin the software from critical level to its own removal Software testing is done while coding by the developers and thorough testing is conducted by testing experts at various levels of code such as module testing Software Engineering Tutorial program testing product testing in house testing and testing the product at
33. some other developer This becomes tedious or at times impossible if all developers do not follow some standard programming style to code the program An appropriate programming style includes using function and variable names relevant to the intended task using well placed indentation commenting code for the convenience of reader and overall presentation of code This makes the program code readable and understandable by all which in turn makes debugging and error solving easier Also proper coding style helps ease the documentation and updation Coding Guidelines Practice of coding style varies with organizations operating systems and language of coding itself The following coding elements may be defined under coding guidelines of an organization e Naming conventions This section defines how to name functions variables constants and global variables e Indenting This is the space left at the beginning of line usually 2 8 whitespace or single tab e Whitespace It is generally omitted at the end of line e Operators Defines the rules of writing mathematical assignment and logical operators For example assignment operator should have space before and after it as in x 2 e Control Structures The rules of writing if then else case switch while until and for control flow statements solely and in nested fashion e Line length and wrapping Defines how many characters should be there in one l
34. stress testing regression testing Testing Approaches Tests can be conducted based on two approaches 1 Functionality testing 2 Implementation testing When functionality is being tested without taking the actual implementation in concern it is known as black box testing The other side is known as white box testing where not only functionality is tested but the way it is implemented is also analyzed Exhaustive tests are the best desired method for a perfect testing Every single possible value in the range of the input and output values is tested It is not 81 Software Engineering Tutorial possible to test each and every value in real world scenario if the range of values is large Black box testing It is carried out to test functionality of the program and also called Behavioral testing The tester in this case has a set of input values and respective desired results On providing input if the output matches with the desired results the program is tested ok and problematic otherwise output gt input gt In this testing method the design and structure of the code are not known to the tester and testing engineers and end users conduct this test on the software Black box testing techniques Equivalence class The input is divided into similar classes If one element of a class passes the test it is assumed that all the class is passed Boundary values The input is divided into
35. system This logical data may contain both functional data and control data e Simple if number of record types are low e Complex if number of record types are high e Average in between simple and complex External Interface Files Software system may need to share its files with some external software or it may need to pass the file for processing or as parameter to some function All these files are counted as external interface files e Simple if number of record types in shared file are low e Complex if number of record types in shared file are high e Average in between simple and complex External Inquiry An inquiry is a combination of input and output where user sends some data to inquire about as input and the system responds to the user with the output of inquiry processed The complexity of a query is more than External Input and External Output Query is said to be unique if its input and output are unique in terms of format and data e Simple if query needs low processing and yields small amount of output data e Complex if query needs high process and yields large amount of output data 71 Average in between simple and complex Software Engineering Tutorial Each of these parameters in the system is given weightage according to their class and complexity The table below mentions the weightage given to each parameter Parameter Simple Inputs 3 Outputs 4 Enquiry 3 Files 7 Interfaces 5
36. to the ever changing world of technology and business environment 91 Software Engineering Tutorial Perfective Maintenance This includes modifications and updates done in order to keep the software usable over long period of time It includes new features new user requirements for refining the software and improve its reliability and performance Preventive Maintenance This includes modifications and updations to prevent future problems of the software It aims to attend problems which are not significant at this moment but may cause serious issues in future Cost of Maintenance Reports suggest that the cost of maintenance is high A study on estimating software maintenance found that the cost of maintenance is as high as 67 of the cost of entire software process cycle Hequirement Designing Implementation gt Testing On an average the cost of software maintenance is more than 50 of all SDLC phases There are various factors which trigger maintenance cost go high such as Real world factors affecting Maintenance Cost The standard age of any software is considered up to 10 to 15 years Older softwares which were meant to work on slow machines with less memory and storage capacity cannot keep themselves challenging against newly coming enhanced softwares on modern hardware 88 Software Engineering Tutorial e As technology advances it becomes costly to maintain old software e Most maintena
37. under column conditions and the prospective actions under column Actions Conditions Actions Rules Shows Connected N N N N Y Y Y Y Conditions Ping is Working N N Y Y N N Y Y Opens Website Y N Y N Y N Y N Check network cable X Check internet router X A X X Actions Restart Web Browser X Contact Service provider X X X X X X Do no action Table Decision Table In house Internet Troubleshooting Entity Relationship Model Entity Relationship model is a type of database model based on the notion of real world entities and relationship among them We can map real world scenario onto ER database model ER Model creates a set of entities with their attributes a set of constraints and relation among them 50 Software Engineering Tutorial ER Model is best used for the conceptual design of database ER Model can be represented as follows Fe Ed TA attribute J attribute Entity relationship Entity Entity An entity in ER Model is a real world being which has some properties called attributes Every attribute is defined by its corresponding set of values called domain For example Consider a school database Here a student is an entity Student has various attributes like name id age and class etc Relationship The logical association among entities is called relationship Relationships are mapped with entities in various ways Mapping cardinalities define the number of associations between two entities Map
38. where they were used or changed Testing Levels Testing itself may be defined at various levels of SDLC The testing process runs parallel to software development Before jumping on the next stage a stage is tested validated and verified Testing separately is done just to make sure that there are no hidden bugs or issues left in the software Software is tested on various levels Unit Testing While coding the programmer performs some tests on that unit of program to know if it is error free Testing is performed under white box testing approach Unit testing helps developers decide that individual units of the program are working as per requirement and are error free Integration Testing Even if the units of software are working fine individually there is a need to find out if the units if integrated together would also work without errors For example argument passing and data updation etc 83 Software Engineering Tutorial System Testing The software is compiled as product and then it is tested as a whole This can be accomplished using one or more of the following tests Functionality testing Tests all functionalities of the software against the requirement Performance testing This test proves how efficient the software is It tests the effectiveness and average time taken by the software to do desired task Performance testing is done by means of load testing and stress testing where the software is put under
39. widely used to measure the size of software Function Point concentrates on functionality provided by the system Features and functionality of the system are used to measure the software complexity Function point counts on five parameters named as External Input External Output Logical Internal Files External Interface Files and External Inquiry To consider the complexity of software each parameter is further categorized as simple average or complex software Program External Programs Let us see parameters of function point External Input Every unique input to the system from outside is considered as external input Uniqueness of input is measured as no two inputs should have same formats These inputs can either be data or control parameters e Simple if input count is low and affects less internal files e Complex if input count is high and affects more internal files 70 Software Engineering Tutorial e Average in between simple and complex External Output All output types provided by the system are counted in this category Output is considered unique if their output format and or processing are unique e Simple if output count is low e Complex if output count is high e Average in between simple and complex Logical Internal Files Every software system maintains internal files in order to maintain its functional information and to function properly These files hold logical data of the
40. ABSOLUTE BEGINNERS www tutorialspoint com SIMPLE EASY LEARNING About the tutorial Software Engineering Tutorial This tutorial provides you the basic understanding of software product software design and development process software project management and design complexities At the end of the tutorial you should be equipped with well understanding of software engineering concepts Audience This tutorial is designed for the readers pursuing education in software development domain and all enthusiastic readers Prerequisites This tutorial is designed and developed for absolute beginners Though awareness about software systems software development process and computer fundamentals would be beneficial Copyright amp Disclaimer Copyright 2014 by Tutorials Point I Pvt Ltd All the content and graphics published in this e book are the property of Tutotorials Point I Pvt Ltd The user of this e book is prohibited to reuse retain copy distribute or republish any contents or a part of contents of this e book in any manner without written consent of the publisher We strive to update the contents of our website and tutorials as timely and as precisely as possible however the contents may contain inaccuracies or errors Tutorials Point I Pvt Ltd provides no guarantee regarding the accuracy timeliness or completeness of our website or its contents including this tutorial If you discover any errors on o
41. ARE SYSTEM ANALYST WE 33 SOFTWARE METRICS AND MEASURES nsnsnssnssssnssssessrssssesersessesessesresessresrsessreresessrsreseeresessreresesresreseereseeseeees 34 SOFTWARE DESIGN BASICS esse sees seek Ee ne oe ge de Rd oe ad ee de De Ge NG ee GE be ge Ge Sek od ee Ge dee ee EE ge died 36 SOFTWARE DE SIGN CEV ES ee 36 BV RUZ FO oe es E T E E ee Ee De E ee Ee Doe 37 COI CORR ENG ee E E E E E A A S A ER GE N oe ee ere 37 ele 37 COUPLING AND ga e NEE 38 EE 38 COUPON oe EE EE ORE EE EE EE EE RE EE 39 DESIGN VERIFICATION AR OE EE AE EE OE EE EE rand 39 SOFTWARE ANALYSIS AND DESIGN TOOLS eise iese sos oe See Soe ie bee oe Gee ee oes ee Ge ee ee ie ee Ge 41 AT ON Re 41 Poe Oy ER OE OE EE OE OE RE ORR AE N AE ie 41 DECOM ION GES ao io E Ged SG oe OE E eN OG ie E GE GR Re oe ee GE Ee 41 Lov ie de SERE EE EE ee eee EE EO EE Ne 42 STRUCTURE CHAR RE OE ET RR OE OE OE OE RE EE OE EE N E 43 HIPO DIAGRAM ER N EE Ee 45 ads eN EER OE OE OE EE ER fee EDE 46 Steet teg died OER EE RE EE EE AO RE OE Ed 47 eege 47 PUDO ODE eg 48 EE 49 Base TADE RE NE ER ER EE AE EE ER AE OE HO N 49 6de Boek oi mt fe EE 49 et 50 ENTIDERELATIONSHIP MODEL osse is ese EE va ee ee EG Ee ee ge cate ee Ee Ge ei ee EE ai 50 DATA DIC TION AR Eden ee ee ei eo oe ee ee Ee es Go EE 51 Requirement of Data Dictionary ees ee ee ee ee ee ee dee ee ee ee ee Ee ee 51 let 52 I Sas se gate se css AO EE IE EE EE EE E OER OO EE NE ER 52 EE 52 TD OO OT AE OE EE OE EE EE EE EE EN 53
42. Tools Upper CASE tools are used in planning analysis and design stages of SDLC e Lower Case Tools Lower CASE tools are used in implementation testing and maintenance e Integrated Case Tools Integrated CASE tools are helpful in all the stages of SDLC from Requirement gathering to Testing and documentation CASE tools can be grouped together if they have similar functionality process activities and capability of getting integrated with other tools Scope of Case Tools The scope of CASE tools goes throughout the SDLC Now we briefly go through various CASE tools Diagram tools These tools are used to represent system components data and control flow among various software components and system structure in a graphical form For example Flow Chart Maker tool for creating state of the art flowcharts Process Modeling Tools Process modeling is method to create software process model which is used to develop the software Process modeling tools help the managers to choose a process model or modify it as per the requirement of software product For example EPF Composer 101 Software Engineering Tutorial Project Management Tools These tools are used for project planning cost and effort estimation project scheduling and resource planning Managers have to strictly comply project execution with every mentioned step in software project management Project management tools help in storing and sharing project information
43. adigm All the phases of SDLC will function one after another in linear manner That is when the first phase is finished then only the second phase will start and so on 10 Software Engineering Tutorial Reauirement oer System wers SW vos Waterfall Model ven L Operations amp Maintenance This model assumes that everything is carried out and taken place perfectly as planned in the previous stage and there is no need to think about the past issues that may arise in the next phase This model does not work smoothly if there are some issues left at the previous step The sequential nature of model does not allow us to go back and undo or redo our actions This model is best suited when developers already have designed and developed similar software in the past and are aware of all its domains Iterative Model This model leads the software development process in iterations It projects the process of development in cyclic manner repeating every step after every cycle of SDLC process a E a e e E EI E a a E n 1 iteration n n 1 The software is first developed on very small scale and all the steps are followed which are taken into consideration Then on every next iteration more features and modules are designed coded tested and added to the software Every cycle produces a software which is complete in itself and has more features and capabilities than that of the previous one After
44. and process measures close to normal 8 Organizational stability The average effective global activity rate in an evolving E type system is invariant over the lifetime of the product Software Paradigms Software paradigms refer to the methods and steps which are taken while designing the software There are many methods proposed and are implemented But we need to see where in the software engineering concept these paradigms stand These can be combined into various categories though each of them is contained in one another software Development Programming Software Design Programming paradigm is a subset of Software design paradigm which is further a subset of Software development paradigm Software Development Paradigm This paradigm is known as software engineering paradigms where all the engineering concepts pertaining to the development of software are applied It includes various researches and requirement gathering which helps the software product to build It consists of Software Engineering Tutorial Requirement gathering Software design Programming Software Design Paradigm This paradigm is a part of Software Development and includes Design Maintenance Programming Programming Paradigm This paradigm is related closely to programming aspect of software development This includes Coding Testing Integration Need of Software Engineering The need of software engineering ari
45. and random cohesion which might be the result of breaking the program into smaller modules for the sake of modularization Because it is unplanned it may serve confusion to the programmers and is generally not accepted e Logical cohesion When logically categorized elements are put together into a module it is called logical cohesion e Emporal Cohesion When elements of module are organized such that they are processed at a similar point of time it is called temporal cohesion e Procedural cohesion When elements of module are grouped together which are executed sequentially in order to perform a task it is called procedural cohesion e Communicational cohesion When elements of module are grouped together which are executed sequentially and work on same data information it is called communicational cohesion e Sequential cohesion When elements of module are grouped because the output of one element serves as input to another and so on it is called sequential cohesion e Functional cohesion It is considered to be the highest degree of cohesion and it is highly expected Elements of module in functional cohesion are grouped because they all contribute to a single well defined function It can also be reused 38 Software Engineering Tutorial Coupling Coupling is a measure that defines the level of inter dependability among modules of a program It tells at what level the modules interfere and interact with each
46. are engineering process with only one difference it is carried out always after reverse engineering Program specifications Forward Re engineered from Reverse _ Engineering Software Engineering 92 Software Engineering Tutorial Component reusability A component is a part of software program code which executes an independent task in the system It can be a small module or sub system itself Example The login procedures used on the web can be considered as components printing system in software can be seen as a component of the software Components have high cohesion of functionality and lower rate of coupling i e they work independently and can perform tasks without depending on other modules In OOP the objects are designed are very specific to their concern and have fewer chances to be used in some other software In modular programming the modules are coded to perform specific tasks which can be used across number of other software programs There is a whole new vertical which is based on re use of software component and is known as Component Based Software Engineering CBSE communication Gomparart a interfaces p Re use can be done at various levels e Application level Where an entire application is used as sub system of new software e Component level Where sub system of an application is used e Modules level Where functional modules are re used Software components provid
47. aries of the project by clearly defining what would be done in the project and what would not be done This makes project to contain limited and quantifiable tasks which can easily be documented and in turn avoids cost and time overrun During Project Scope management it is necessary to e Define the scope e Decide its verification and control e Divide the project into various smaller parts for ease of management 17 Software Engineering Tutorial Verify the scope Control the scope by incorporating changes to the scope Project Estimation For an effective management accurate estimation of various measures is a must With the correct estimation managers can manage and control the project more efficiently and effectively Project estimation may involve the following Software size estimation Software size may be estimated either in terms of KLOC Kilo Line of Code or by calculating number of function points in the software Lines of code depend upon coding practices Function points vary according to the user or software requirement Effort estimation The manager estimates efforts in terms of personnel requirement and man hour required to produce the software For effort estimation software size should be known This can either be derived by manager s experience historical data of organization or software size can be converted into efforts by using some standard formulae Time estimation Once size and efforts ar
48. ate technical documentation of code User documentation This documentation is different from all the above explained All previous documentations are maintained to provide information about the software and its development process But user documentation explains how the software product should work and how it Should be used to get the desired results These documentations may include software installation procedures how to guides user guides uninstallation method and special references to get more information like license updation etc Software Implementation Challenges There are some challenges faced by the development team while implementing the software Some of them are mentioned below Code reuse Programming interfaces of present day languages are very sophisticated and are equipped huge library functions Still to bring the cost down of end product the organization management prefers to re use the code which was created earlier for some other software There are huge issues faced by programmers for compatibility checks and deciding how much code to re use Version Management Every time a new software is issued to the customer developers have to maintain version and configuration related documentation This documentation needs to be highly accurate and available on time Target Host The software program which is being developed in the organization needs to be designed for host machines at the customers end 78
49. ber of work units for each task e Calculate total time required for the project from start to finish Resource management All elements used to develop a software product may be assumed as resource for that project This may include human resource productive tools and software libraries The resources are available in limited quantity and stay in the organization as a pool of assets The shortage of resources hampers development of the project and it can lag behind the schedule Allocating extra resources increases development cost in the end It is therefore necessary to estimate and allocate adequate resources for the project Resource management includes e Defining proper organization project by creating a project team and allocating responsibilities to each team member e Determining resources required at a particular stage and their availability 20 Software Engineering Tutorial e Manage Resources by generating resource request when they are required and de allocating them when they are no more needed Project Risk Management Risk management involves all activities pertaining to identification analyzing and making provision for predictable and non predictable risks in the project Risk may include the following e Experienced staff leaving the project and new staff coming in e Change in organizational management e Requirement change or misinterpreting requirement e Under estimation of required time and resources
50. cess briefly Feasibility study When the client approaches the organization for getting the desired product developed it comes up with a rough idea about what all functions the software must perform and which all features are expected from the software Referencing to this information the analysts do a detailed study about whether the desired system and its functionality are feasible to develop This feasibility study is focused towards goal of the organization This study analyzes whether the software product can be practically materialized in terms of implementation contribution of project to organization cost constraints and as per values and objectives of the organization It explores technical aspects of the 91 Software Engineering Tutorial project and product such as usability maintainability productivity and integration ability The output of this phase should be a feasibility study report that should contain adeguate comments and recommendations for management about whether or not the project should be undertaken Requirement Gathering If the feasibility report is positive towards undertaking the project next phase starts with gathering requirements from the user Analysts and engineers communicate with the client and end users to know their ideas on what the software should provide and which features they want the software to include Software Requirement Specification SRS SRS is a document created by system
51. class and High order functions These functions have capability to accept another function as argument or they return other functions as results e Pure functions These functions do not include destructive updates that is they do not affect any I O or memory and if they are not in use they can easily be removed without hampering the rest of the program e Recursion Recursion is a programming technique where a function calls itself and repeats the program code in it unless some pre defined condition matches Recursion is the way of creating loops in functional programming e Strict evaluation It is a method of evaluating the expression passed to a function as an argument Functional programming has two types of evaluation methods strict eager or non strict lazy Strict evaluation always evaluates the expression before invoking the function Non strict evaluation does not evaluate the expression unless it is needed e A calculus Most functional programming languages use A calculus as their type systems A expressions are executed by evaluating them as they occur 75 Software Engineering Tutorial Common Lisp Scala Haskell Erlang and F are some examples of functional programming languages Programming style Programming style is set of coding rules followed by all the programmers to write the code When multiple programmers work on the same software project they frequently need to work with the program code written by
52. cs depends upon the actual implementation of program and its measures which are computed directly from the operators and operands from source code in static manner It allows to evaluate testing time vocabulary size difficulty errors and efforts for C C Java source code According to Halstead A computer program is an implementation of an algorithm considered to be a collection of tokens which can be classified as either operators Or Operands Halstead metrics think a program as sequence of operators and their associated operands He defines various indicators to check complexity of module Following table states the parameters and the meanings 91 Software Engineering Tutorial Parameter Meaning ni Number of unique operators n2 Number of unique operands Ni Number of total occurrence of operators N2 Number of total occurrence of operands When we select source file to view its complexity details in Metric Viewer the following result is seen in Metric Report Metric Meaning Mathematical Representation n Vocabulary ni n2 N Size Ni N2 V Volume Length Log2 Vocabulary D Difficulty n1 2 N1 n2 E Efforts Difficulty Volume B Errors Volume 3000 T Testing time Time Efforts S where S 18 seconds Cyclomatic Complexity Measures Every program encompasses statements to execute in order to perform some task and other decision making statements that decide what statements need to be executed These deci
53. der version control system if it is ready to launch 85 Software Engineering Tutorial Testing vs Quality Control amp Assurance and Audit We need to understand that software testing is different from software quality assurance software quality control and software auditing Software quality assurance These are software development process monitoring means by which it is assured that all the measures are taken as per the standards of organization This monitoring is done to make sure that proper software development methods were followed Software quality control This is a system to maintain the quality of software product It may include functional and non functional aspects of software product which enhance the goodwill of the organization This system makes sure that the customer is receiving quality product for their requirement and the product certified as fit for use Software audit This is a review of procedure used by the organization to develop the software A team of auditors independent of development team examines the software process procedure requirements and other aspects of SDLC The purpose of software audit is to check that software and its development process both conform standards rules and regulations 86 Software Engineering Tutorial Software Maintenance Overview Software maintenance is widely accepted part of SDLC now a days It stands for all the modifications and updations done aft
54. dule 43 Software Engineering Tutorial Control Module Module Module Module SUb Module Library Module e Condition It is represented by small diamond at base of the module It depicts that control module can select any of sub routine based on some condition Module e Jump An arrow is shown pointing inside the module to depict that the control will jump in the middle of the sub module Module Module e Loop A curved arrow represents loop in the module All sub modules covered by loop repeat execution of module 44 Software Engineering Tutorial Module KA Module Module Module e Data flow A directed arrow with empty circle at the end represents data flow Module Module e Control flow A directed arrow with filled circle at the end represents control flow Module HIPO Diagram Hierarchical Input Process Output HIPO diagram is a combination of two organized methods to analyze the system and provide the means of documentation HIPO model was developed by IBM in year 1970 HIPO diagram represents the hierarchy of modules in the software system Analyst uses HIPO diagram in order to obtain high level view of system functions It L 45 Software Engineering Tutorial decomposes functions into sub functions in a hierarchical manner It depicts the functions performed by system HIPO diagrams are good for documentation purpose Their graphical re
55. e EA EE EE AR EE EE RA EE EA EG 10 Operation and Mamntenanie iese EE oe Ge Ge ie Ge RE ie N id 10 SOFTWARE DEVELOPMENT PARADIGM ee ees sesse ss esse esse see soe ese sees see sees dese seed Goede ee dee RK EE GE eg RK ee 10 Water al MOO bee n Ee GE ee ee EA oe EE Re N Do 10 haa ee KA es eel NEE EE EE EE EE Oe EE EE OR ON 11 edge di eie AE EE OE OE OE EE ER EE EE OE EE IE 12 IOS RE EE OE OR EE N EE OE EE EO ey 12 Ba ng OG ON EE AE OE EE EE EE OE ELE OE EE OE N 14 SOFTWARE PROJECT MANAGEMENT ss osse ds ves ese oe seke ge ee ee oe OE ees Ee Si oe Gode ee de Go Ge ee Se be gee Ged 15 ek Vd ele OE EE OR ED EE EE EE tae 15 NEED OF SOFTWARE PROJECT MANAGEMENT ANNER 15 SOFTWARE PROJECT Ee 16 Manada e 16 Managing Proje E 17 SOFTWARE MANAGEMENT ECHTEN 17 PROIECTE Ee 17 DOPE MANAGEMENT E e oe E E E E A N T EE AE ee IG N E A OA E 17 ROME CT nn date E 18 PROJECT ESTIMATION TECHNIQUES Si oe GE RD Ge Ge De ee Ge Di 19 POCO eet Ge Ge ee OE ee od Ge EE 19 Empia Esman ER ee e TEE 19 verse ps CED dd ie EE RE OE N EE N E 20 RESOURCE Ee EE 20 PROJECT RISK MANAGEMENT Ai oe eo ne ee tenia oo GO Ee ee ee De OD EG OE ee 21 Risk Management Process ae ee ee Ge RE De eh oe ee GR RD ee Dee ee Ge oe Ge 21 PROJECT EXECUTION AND MONITORING EE 21 PROJECT COMMUNICATION MANAGEMENT iss sede sei ee ee seed oos ee ee eg Gee ee ie oe eN Ge ek eg oe ee Ge de 22 CONFIGURATION MANAGEMENT ss see ees ees ee Ge oe E ek Ge Ge eb ee Ge dee ee de ee eg ee ee Ge Ge EE Ge ei ed ee 23
56. e ee ee ee ee de ee ee ee Re ee ee 78 SOFTWARE TESTING OVERVIEW is do oosesses ees ies ede id sesde os de ve dee se de ee seed De de oe Dee ee see eed eed do ee de se Ge ee 80 SOFTWARE VAUDA TION EE EO RE EE EO ET 80 EE VERIFICA TION se ese outta Ge ee ei er ee Ge ee ER Oe Gee ie ee Pe Ee Ge GE N er OE ee 80 MANUAL VS AUTOMATED TES TING ii es ee Gr ee ee de Ee ee eran Ge Ge ee eo etree teen 81 In le ee se ie ee ee ee ee cer EG GE GE ee de GE ee Ee 81 BO DON TE AG AE E EE EE N EE RE EE EN N 82 WA dio COSC AG AE N EE N OE N 82 TESTING AS OER WAR AE AR ME N DEE ER OE ER OG 83 CATE FCS dle AE TE EE EE sani E E suiamaiewmmundiennodietuacunionsendions 83 WCC OF IOI TESNO es SS be N ee n ie SR De ee De oie DS ie eie EN PG 83 SWEM TESE EEN 84 Acceptance TESNO E 84 Regresso Eed 84 TES NS DO COMENTA NON EE 84 Poe TeS de AE RE EE EE EE EE RE ON 85 WAE BEng TOS n ed PE On on ae ae ee ee ae ee 85 AT ai glo ORE EE EE E EE OE OE OE EE EE OE OR EE IE Ne 85 TESTING VS QUALITY CONTROL amp ASSURANCE AND AUDIT 86 SOFTWARE MAINTENANCE OVER VIEW osse ege Ge se Ses Ge de ede ke oog ee oe oe eo si Ge si ee Ge de eb Ee ds eg ee 87 EREECHEN 87 COSTOF IS Vd EE 88 Real world factors affecting Maintenance Coste 88 Software end factors AFFECTING Maintenance Coste 89 MAINTENANCE ACTIVITIE C esse een ee Des Ee Ee ee De Ee ee dene ance ee Ee sane Ee ie POS 89 SOFTWARE EERSTEN 90 Re Engineering ele ONE EE OR EE EE EE EO N OE ES 91 Reverse ag ie EE OE OE EE EE OE ON 92
57. e estimated the time required to produce the software can be estimated Efforts required is segregated into sub categories as per the requirement specifications and interdependency of various components of software Software tasks are divided into smaller tasks activities or events by Work Breakthrough Structure WBS The tasks are scheduled on day to day basis or in calendar months The sum of time required to complete all tasks in hours or days is the total time invested to complete the project Cost estimation 18 Software Engineering Tutorial This might be considered as the most difficult of all because it depends on more elements than any of the previous ones For estimating project cost it is required to consider e Size of the software e Software quality e Hardware e Additional software or tools licenses etc e Skilled personnel with task specific skills e Travel involved e Communication e Training and support Project Estimation Techniques We discussed various parameters involving project estimation such as size effort time and cost Project manager can estimate the listed factors using two broadly recognized techniques Decomposition Technique This technique assumes the software as a product of various compositions There are two main models e Line of Code Here the estimation is done on behalf of number of line of codes in the software product e Function Points Here the estimation is done on be
58. e interfaces which can be used to establish communication among different components Reuse Process Two kinds of method that can be adopted either by keeping requirements same and adjusting components or by keeping components same and modifying requirements 93 Software Engineering Tutorial Specify fe Specify Requirements Components search suitable Components Stress d Incorporate Components Components Repository i Requirement Specification The functional and non functional requirements are specified which a software product must comply to with the help of existing system user input or both Design This is also a standard SDLC process step where requirements are defined in terms of software parlance Basic architecture of system as a whole and its sub systems are created Specify Components By studying the software design the designers segregate the entire system into smaller components or sub systems One complete software design turns into a collection of a huge set of components working together Search Suitable Components The software component repository is referred by designers to search for the matching component on the basis of functionality and intended software requirements Incorporate Components All matched components are packed together to shape them as complete software 94 Software Engineering Tutorial Software CASE Tools Overview CASE stands for Computer Aided
59. ence Top down design is more suitable when the software solution needs to be designed from scratch and specific details are unknown Bottom up Design The bottom up design model starts with most specific and basic components It proceeds with composing higher level of components by using basic or lower level components It keeps creating higher level components until the desired system is not evolved as one single component With each higher level the amount of abstraction is increased Bottom up strategy is more suitable when a system needs to be created from some existing system where the basic primitives can be used in the newer system Both top down and bottom up approaches are not practical individually Instead a good combination of both is used 57 Software Engineering Tutorial Software User Interface Design User interface is the front end application view to which user interacts in order to use the software User can manipulate and control the software as well as hardware by means of user interface Today user interface is found at almost every place where digital technology exists right from computers mobile phones cars music players airplanes ships etc User interface is part of software and is designed in such a way that it is expected to provide the user insight of the software UI provides fundamental platform for human computer interaction UI can be graphical text based audio video based depending u
60. ents Some of them are explained below 29 Software Engineering Tutorial Interviews Interviews are strong medium to collect requirements Organization may conduct several types of interviews such as e Structured closed interviews where every single information to gather is decided in advance they follow pattern and matter of discussion firmly e Non structured open interviews where information to gather is not decided in advance more flexible and less biased e Oral interviews e Written interviews e One to one interviews which are held between two persons across the table e Group interviews which are held between groups of participants They help to uncover any missing requirement as numerous people are involved Surveys Organization may conduct surveys among various stakeholders by querying about their expectation and requirements from the upcoming system Questionnaires A document with pre defined set of objective questions and respective options is handed over to all stakeholders to answer which are collected and compiled A shortcoming of this technique is if an option for some issue is not mentioned in the questionnaire the issue might be left unattended Task analysis Team of engineers and developers may analyze the operation for which the new system is required If the client already has some software to perform certain operation it is studied and requirements of proposed system are collected
61. equences of actions should be required in similar situations Identical terminology should be used in prompts menus and help screens Consistent commands should be employed throughout e Enable frequent users to use short cuts The user s desire to reduce the number of interactions increases with the frequency of use Abbreviations function keys hidden commands and macro facilities are very helpful to an expert user 64 Software Engineering Tutorial Offer informative feedback For every operator action there should be some system feedback For freguent and minor actions the response must be modest while for infreguent and major actions the response must be more substantial Design dialog to yield closure Sequences of actions should be Organized into groups with a beginning middle and end The informative feedback at the completion of a group of actions gives the operators the satisfaction of accomplishment a sense of relief the signal to drop contingency plans and options from their minds and this indicates that the way ahead is clear to prepare for the next group of actions Offer simple error handling As much as possible design the system so the user will not make a serious error If an error is made the system should be able to detect it and offer simple comprehensible mechanisms for handling the error Permit easy reversal of actions This feature relieves anxiety since the user knows that errors can be und
62. er the delivery of software product There are number of reasons why modifications are required some of them are briefly mentioned below e Market Conditions Policies which changes over the time such as taxation and newly introduced constraints like how to maintain bookkeeping may trigger need for modification e Client Requirements Over the time customer may ask for new features or functions in the software e Host Modifications If any of the hardware and or platform such as operating system of the target host changes software changes are needed to keep adaptability e Organization Changes If there is any business level change at client end such as reduction of organization strength acquiring another company organization venturing into new business need to modify in the Original software may arise Types of maintenance In a software lifetime type of maintenance may vary based on its nature It may be just a routine maintenance tasks as some bug discovered by some user or it may be a large event in itself based on maintenance size or nature Following are some types of maintenance based on their characteristics e Corrective Maintenance This includes modifications and updations done in order to correct or fix problems which are either discovered by user or concluded by user error reports e Adaptive Maintenance This includes modifications and updations applied to keep the software product up to date and tuned
63. esign phase are in formal notation form then their associated tools for verification should be used otherwise a thorough design review can be used for verification and validation By structured verification approach reviewers can detect defects that might be caused by overlooking some conditions A good design review is important for good software design accuracy and quality 39 Software Engineering Tutorial 40 Software Engineering Tutorial Software Analysis and Design Tools Software analysis and design includes all activities which help the transformation of requirement specification into implementation Requirement specifications specify all functional and non functional expectations from the software These requirement specifications come in the shape of human readable and understandable documents to which a computer has nothing to do Software analysis and design is the intermediate stage which helps human readable requirements to be transformed into actual code Let us see few analysis and design tools used by software designers Data Flow Diagram Data Flow Diagram DFD is a graphical representation of flow of data in an information system It is capable of depicting incoming data flow outgoing data flow and stored data The DFD does not mention anything about how data flows through the system There is a prominent difference between DFD and Flowchart The flowchart depicts flow of control in program modu
64. et us see few responsibilities that a project manager shoulders Managing People e Act as project leader e Lesion with stakeholders e Managing human resources e Setting up reporting hierarchy etc 16 Software Engineering Tutorial Managing Project e Defining and setting up project scope e Managing project management activities e Monitoring progress and performance e Risk analysis at every phase e Take necessary step to avoid or come out of problems e Act as project spokesperson Software Management Activities Software project management comprises of a number of activities which contains planning of project deciding scope of software product estimation of cost in various terms scheduling of tasks and events and resource management Project management activities may include e Project Planning e Scope Management e Project Estimation Project Planning Software project planning is task which is performed before the production of software actually starts It is there for the software production but involves no concrete activity that has any direct connection with the software production rather it is a set of multiple processes which facilitates software production Project planning may include the following Scope Management It defines scope of the project this includes all the activities process need to be done in order to make a deliverable software product Scope management is essential because it creates bound
65. f the code gets executed Design Process Software design process can be perceived as series of well defined steps Though it varies according to design approach function oriented or object oriented yet It may have the following steps involved A solution design is created from requirement or previous used system and or system sequence diagram Objects are identified and grouped into classes on behalf of similarity in attribute characteristics Class hierarchy and relation among them is defined Application framework is defined 56 Software Engineering Tutorial Software Design Approaches Here are two generic approaches for software designing Top Down Design We know that a system is composed of more than one sub systems and it contains a number of components Further these sub systems and components may have their own set of sub systems and components and creates hierarchical structure in the system Top down design takes the whole software system as one entity and then decomposes it to achieve more than one sub system or component based on some characteristics Each sub system or component is then treated as a system and decomposed further This process keeps on running until the lowest level of system in the top down hierarchy is achieved Top down design starts with a generalized model of system and keeps on defining the more specific part of it When all the components are composed the whole system comes into exist
66. formation among sub tasks determines the flow of GUI contents in the software GUI Design and implementation Designers after having information about requirements tasks and user environment design the GUI and implements into code and embed the GUI with working or dummy software in the background It is then self tested by the developers 63 Software Engineering Tutorial e Testing GUI testing can be done in various ways Organization can have in house inspection direct involvement of users and release of beta version are few of them Testing may include usability compatibility user acceptance etc GUI Implementation Tools There are several tools available using which the designers can create entire GUI on a mouse click Some tools can be embedded into the software environment IDE GUI implementation tools provide powerful array of GUI controls For software customization designers can change the code accordingly There are different segments of GUI tools according to their different use and platform Example Mobile GUI Computer GUI Touch Screen GUI etc Here is a list of few tools which come handy to build GUI e FLUID e AppInventor Android e LucidChart e Wavemaker e Visual Studio User Interface Golden rules The following rules are mentioned to be the golden rules for GUI design described by Shneiderman and Plaisant in their book Designing the User Interface e Strive for consistency Consistent s
67. g 3 Structured Coding In reference with top down analysis structured coding sub divides the modules into further smaller units of code in the 91 Software Engineering Tutorial order of their execution Structured programming uses control structure which controls the flow of the program whereas structured coding uses control structure to organize its instructions in definable patterns Functional Programming Functional programming is style of programming language which uses the concepts of mathematical functions A function in mathematics should always produce the same result on receiving the same argument In procedural languages the flow of the program runs through procedures i e the control of program is transferred to the called procedure While control flow is transferring from one procedure to another the program changes its state In procedural programming it is possible for a procedure to produce different results when it is called with the same argument as the program itself can be in different state while calling it This is a property as well as a drawback of procedural programming in which the sequence or timing of the procedure execution becomes important Functional programming provides means of computation as mathematical functions which produces results irrespective of program state This makes it possible to predict the behavior of the program Functional programming uses the following concepts First
68. g activated at any given time Say a software has multiple modules then only one of all the modules can be found active at any time of execution In software design concurrency is implemented by splitting the software into multiple independent units of execution like modules and executing them in parallel In other words concurrency provides capability to the software to execute more than one part of code in parallel to each other It is necessary for the programmers and designers to recognize those modules which can be made parallel execution Example The spell check feature in word processor is a module of software which runs along side the word processor itself 37 Software Engineering Tutorial Coupling and Cohesion When a software program is modularized its tasks are divided into several modules based on some characteristics As we know modules are set of instructions put together in order to achieve some tasks They are though considered as a single entity but may refer to each other to work together There are measures by which the quality of a design of modules and their interaction among them can be measured These measures are called coupling and cohesion Cohesion Cohesion is a measure that defines the degree of intra dependability within elements of a module The greater the cohesion the better is the program design There are seven types of cohesion namely e Co incidental cohesion It is unplanned
69. half of number of function points in the software product Empirical Estimation Technique This technique uses empirically derived formulae to make estimation These formulae are based on LOC or FPs e Putnam Model This model is made by Lawrence H Putnam which is based on Norden s frequency distribution Rayleigh curve Putnam model maps time and efforts required with software size e COCOMO 19 Software Engineering Tutorial COCOMO stands for Constructive Cost Model developed by Barry W Boehm It divides the software product into three categories of software organic semi detached and embedded Project Scheduling Project Scheduling in a project refers to roadmap of all activities to be done with specified order and within time slot allotted to each activity Project managers tend to define various tasks and project milestones and then arrange them Keeping various factors in mind They look for tasks like in critical path in the schedule which are necessary to complete in specific manner because of task interdependency and strictly within the time allocated Arrangement of tasks which lies out of critical path are less likely to impact over all schedule of the project For scheduling a project it is necessary to e Break down the project tasks into smaller manageable form e Find out various tasks and correlate them e Estimate time frame required for each task e Divide time into work units e Assign adequate num
70. he requirement of real world environment This software has a high degree of evolution as there are various changes in laws taxes etc in the real world situations For example Online trading software E Type software evolution Lehman has given eight laws for E Type software evolution 1 Continuing change An E type software system must continue to adapt to the real world changes else it becomes progressively less useful 2 Increasing complexity As an E type software system evolves its complexity tends to increase unless work is done to maintain or reduce it 3 Conservation of familiarity The familiarity with the software or the knowledge about how it was developed why was it developed in that particular manner etc must be retained at any cost to implement the changes in the system 4 Continuing growth In order for an E type system intended to resolve some business problem its size of implementing the changes grows according to the lifestyle changes of the business Software Engineering Tutorial 5 Reducing quality An E type software system declines in quality unless rigorously maintained and adapted to a changing operational environment 6 Feedback systems The E type software systems constitute multi loop multi level feedback systems and must be treated as such to be successfully modified or improved 7 Self regulation E type system evolution processes are self regulating with the distribution of product
71. he risk and uncertainty rises multifold with respect to the size of the project even when the project is developed according to set methodologies There are tools available which aid for effective project management A few described are Gantt Chart Gantt chart was devised by Henry Gantt 1917 It represents project schedule with respect to time periods It is a horizontal bar chart with bars representing activities and time scheduled for the project activities Weeks 1 2 3 4 5 6 7 8 9 10 Delivery iii 7 O 24 Software Engineering Tutorial PERT Chart Program Evaluation amp Review Technigue PERT chart is a tool that depicts project as network diagram It is capable of graphically representing main events of project in both parallel and consecutive ways Events which occur one after another show dependency of the later event over the previous one Events are shown as numbered nodes They are connected by labeled arrows depicting the sequence of tasks in the project Resource Histogram This is a graphical tool that contains bar or chart representing number of resources usually skilled staff required over time for a project event or phase Resource Histogram is an effective tool for staff planning and coordination Designer 433 2 2 14 Developer O 0 1 2 4 4 3 Tester JO 000222 Total 4 4 5 BiB 6 25 Software Engineering Tutorial 8 6 Mi Designer CT MI Developer a 4 MM Tester KR
72. higher and lower end values If these values pass the test it is assumed that all values in between may pass too Cause effect graphing In both previous methods only one input value at a time is tested Cause input Effect output is a testing technique where combinations of input values are tested in a systematic way Pair wise Testing The behavior of software depends on multiple parameters In pairwise testing the multiple parameters are tested pair wise for their different values State based testing The system changes state on provision of input These systems are tested based on their states and input White box testing It is conducted to test program and its implementation in order to improve code efficiency or structure It is also known as Structural testing 82 Software Engineering Tutorial input output In this testing method the design and structure of the code are known to the tester Programmers of the code conduct this test on the code The below are some White box testing techniques e Control flow testing The purpose of the control flow testing to set up test cases which covers all statements and branch conditions The branch conditions are tested for both being true and false so that all statements can be covered e Data flow testing This testing technique emphasis to cover all the data variables included in the program It tests where the variables were declared and defined and
73. horoughly analyzing understanding the existing system This process can be seen as reverse SDLC model i e we try to get higher abstraction level by analyzing lower abstraction levels An existing system is previously implemented design about which we know nothing Designers then do reverse engineering by looking at the code and try to get the design With design in hand they try to conclude the specifications Thus going in reverse from code to system specification Existing Reverse Program Software _ Engineering Specifications Program Restructuring It is a process to re structure and re construct the existing software It is all about re arranging the source code either in same programming language or from one programming language to a different one Restructuring can have either source code restructuring and data restructuring or both Re structuring does not impact the functionality of the software but enhance reliability and maintainability Program components which cause errors very frequently can be changed or updated with re structuring The dependability of software on obsolete hardware platform can be removed via re structuring Forward Engineering Forward engineering is a process of obtaining desired software from the specifications in hand which were brought down by means of reverse engineering It assumes that there was some software engineering already done in the past Forward engineering is same as softw
74. ign mechanism divides the whole system into smaller functions which provides means of abstraction by concealing the information and their operation These functional modules can share information among themselves by means of information passing and using information available globally Another characteristic of functions is that when a program calls a function the function changes the state of the program which sometimes is not acceptable by other modules Function oriented design works well where the system state does not matter and program functions work on input rather than on a state Design Process e The whole system is seen as how data flows in the system by means of data flow diagram e DFD depicts how functions change data and state of the entire system e The entire system is logically broken down into smaller units known as functions on the basis of their operation in the system e Each function is then described at large Object Oriented Design Object Oriented Design OOD works around the entities and their characteristics instead of functions involved in the software system This design strategies focuses on entities and its characteristics The whole concept of software solution revolves around the engaged entities Let us see the important concepts of Object Oriented Design e Objects All entities involved in the solution design are known as objects For example person banks company and customers are treated as
75. imate product excellent According to Tom DeMarco a Software Engineer You cannot control what you cannot measure By his saying it is very clear how important software measures are Let us see some software metrics e Size Metrics Lines of Code LOC mostly calculated in thousands of delivered source code lines denoted as KLOC e Function Point Count is measure of the functionality provided by the software Function Point count defines the size of functional aspect of the software e Complexity Metrics McCabe s Cyclomatic complexity quantifies the upper bound of the number of independent paths in a program which is 34 Software Engineering Tutorial perceived as complexity of the program or its modules It is represented in terms of graph theory concepts by using control flow graph Quality Metrics Defects their types and causes consequence intensity of severity and their implications define the quality of the product The number of defects found in development process and number of defects reported by the client after the product is installed or delivered at client end define quality of the product Process Metrics In various phases of SDLC the methods and tools used the company standards and the performance of development are software process metrics Resource Metrics Effort time and various resources used represents metrics for resource measurement 35 Software Engineering Tutorial
76. ine mostly a line is 80 characters long Wrapping defines how a line Should be wrapped if is too long 76 Software Engineering Tutorial e Functions This defines how functions should be declared and invoked with and without parameters e Variables This mentions how variables of different data types are declared and defined e Comments This is one of the important coding components as the comments included in the code describe what the code actually does and all other associated descriptions This section also helps creating help documentations for other developers Software Documentation Software documentation is an important part of software process A well written document provides a great tool and means of information repository necessary to Know about software process Software documentation also provides information about how to use the product A well maintained documentation should involve the following documents e Requirement documentation This documentation works as key tool for software designer developer and the test team to carry out their respective tasks This document contains all the functional non functional and behavioral description of the intended software Source of this document can be previously stored data about the software already running software at the client s end clients interview questionnaires and research Generally it is stored in the form of spreadsheet or word processing docume
77. ing and experimenting 14 Software Engineering Tutorial Software Project Management The job pattern of an IT company engaged in software development can be seen Split in two parts e Software Creation e Software Project Management A project is well defined task which is a collection of several operations done in order to achieve a goal for example software development and delivery A Project can be characterized as e Every project may have a unigue and distinct goal e Project is not a routine activity or day to day operation e Project comes with a start and end time e Project ends when its goal is achieved Hence it is a temporary phase in the lifetime of an organization e Project needs adequate resources in terms of time manpower finance material and knowledge bank Software Project A Software Project is the complete procedure of software development from requirement gathering to testing and maintenance carried out according to the execution methodologies in a specified period of time to achieve intended software product Need of software project management Software is said to be an intangible product Software development is a kind of all new stream in world business and there is very little experience in building software products Most software products are tailor made to fit client s requirements The most important is that the underlying technology changes and advances so frequently and rapid
78. ing email by distributing a hardcopy of document or by other mean of effective communication After closure the team moves to next phase or project 22 Software Engineering Tutorial Configuration Management Configuration management is a process of tracking and controlling the changes in software in terms of the requirements design functions and development of the product IEEE defines it as the process of identifying and defining the items in the system controlling the change of these items throughout their life cycle recording and reporting the status of items and change requests and verifying the completeness and correctness of items Generally once the SRS is finalized there is less chance of requirement of changes from user If they occur the changes are addressed only with prior approval of higher management as there is a possibility of cost and time overrun Baseline A phase of SDLC is assumed over if it baselined i e baseline is a measurement that defines completeness of a phase A phase is baselined when all activities pertaining to it are finished and well documented If it was not the final phase its output would be used in next immediate phase Configuration management is a discipline of organization administration which takes care of occurrence of any changes process requirement technological strategical etc after a phase is baselined CM keeps check on any changes done in software Change Co
79. into several well organized elements of solution It is basically concerned with the solution design Benefit of structured design is it gives better understanding of how the problem is being solved Structured design also makes it simpler for designer to concentrate on the problem more accurately Structured design is mostly based on divide and conquer strategy where a problem is broken into several small problems and each small problem is individually solved until the whole problem is solved The small pieces of problem are solved by means of solution modules Structured design emphasis that these modules be well organized in order to achieve precise solution These modules are arranged in hierarchy They communicate with each other A good structured design always follows some rules for communication among multiple modules namely e Cohesion grouping of all functionally related elements e Coupling communication between different modules A good structured design has high cohesion and low coupling arrangements 91 Software Engineering Tutorial Function Oriented Design In function oriented design the system comprises of many smaller sub systems Known as functions These functions are capable of performing significant task in the system The system is considered as top view of all functions Function oriented design inherits some properties of structured design where divide and conquer methodology is used This des
80. les DFDs depict flow of data in the system at various levels It does not contain any control or branch elements Types of DFD Data Flow Diagrams are either Logical or Physical e Logical DFD This type of DFD concentrates on the system process and flow of data in the system For example in a banking software system how data is moved between different entities e Physical DFD This type of DFD shows how the data flow is actually implemented in the system It is more specific and close to the implementation DFD Components DFD can represent source destination storage and flow of data using the following set of components 91 Software Engineering Tutorial Data Flow Process Data Store e Entities Entities are sources and destinations of information data Entities are represented by rectangles with their respective names e Process Activities and action taken on the data are represented by Circle or Round edged rectangles e Data Storage There are two variants of data storage it can either be represented as a rectangle with absence of both smaller sides or as an open sided rectangle with only one side missing e Data Flow Movement of data is shown by pointed arrows Data movement is shown from the base of arrow as its source towards head of the arrow as destination Levels of DFD e Level O Highest abstraction level DFD is known as Level O DFD which depicts the entire information system as
81. ly that the experience of one product may not be applied to the other one All such business and environmental constraints bring 15 Software Engineering Tutorial risk in software development hence it is essential to manage software projects efficiently Quality The image above shows triple constraints for software projects It is an essential part of software organization to deliver quality product keeping the cost within client s budget constrain and deliver the project as per scheduled There are several factors both internal and external which may impact this triple constrain triangle Any of the three factors can severely impact the other two Therefore software project management is essential to incorporate user requirements along with budget and time constraints Software Project Manager A software project manager is a person who undertakes the responsibility of executing the software project Software project manager is thoroughly aware of all the phases of SDLC that the software would go through The project manager may never directly involve in producing the end product but he controls and manages the activities involved in production A project manager closely monitors the development process prepares and executes various plans arranges necessary and adequate resources maintains communication among all team members in order to address issues of cost budget resources time quality and customer satisfaction L
82. ments like forms text script graphic and so on Web tools also provide live preview of what is being developed and how will it look after completion For example Fontello Adobe Edge Inspect Foundation 3 Brackets Quality Assurance Tools Quality assurance in a software organization is monitoring the engineering process and methods adopted to develop the software product in order to ensure conformance of quality as per organization standards QA tools consist of configuration and change control tools and software testing tools For example SoapTest AppsWatch JMeter Maintenance Tools Software maintenance includes modifications in the software product after it is delivered Automatic logging and error reporting techniques automatic error 103 Software Engineering Tutorial ticket generation and root cause Analysis are few CASE tools which help software organization in maintenance phase of SDLC For example Bugzilla for defect tracking HP Ouality Center 104
83. nce engineers are newbie and use trial and error method to rectify problem e Often changes made can easily hurt the original structure of the software making it hard for any subsequent changes e Changes are often left undocumented which may cause more conflicts in future Software end factors affecting Maintenance Cost e Structure of Software Program e Programming Language e Dependence on external environment e Staff reliability and availability Maintenance Activities IEEE provides a framework for sequential maintenance process activities It can be used in iterative manner and can be extended so that customized items and processes can be included Identification amp Tracing _ Maintenance Maintenance FEE Management Activities Acceptance Testing System Testing These activities go hand in hand with each of the following phase e Identification amp Tracing It involves activities pertaining to identification of requirement of modification or maintenance It is generated by user or 89 Software Engineering Tutorial system may itself report via logs or error messages Here the maintenance type is classified also Analysis The modification is analyzed for its impact on the system including safety and security implications If probable impact is severe alternative solution is looked for A set of reguired modifications is then materialized into requirement specifications The cost of modificati
84. nt position of character while typing Cursor is mostly found in blinking state It moves as the user writes or deletes something e Command A command is an executable instruction It may have one or more parameters Output on command execution is shown inline on the screen When output is produced command prompt is displayed on the next line 59 Software Engineering Tutorial Graphical User Interface Graphical User Interface GUI provides the user graphical means to interact with the system GUI can be combination of both hardware and software Using GUI user interprets the software Typically GUI is more resource consuming than that of CLI With advancing technology the programmers and designers create complex GUI designs that work with more efficiency accuracy and speed GUI Elements GUI provides a set of components to interact with software or hardware Every graphical component provides a way to work with the system A GUI system has following elements such as Window manipulating icons tabs Lu Desktop Dr Documents Movies Ja Music Pictures DEVICES LJ Finaca Slider Status bar Window An area where contents of application are displayed Contents in a window can be displayed in the form of icons or lists if the window represents file structure It is easier for a user to navigate in the file system in an exploring window Windows can be minimized resized or maximized to the size
85. nt with the high end software management team This documentation works as foundation for the software to be developed and is majorly used in verification and validation phases Most test cases are built directly from requirement documentation e Software Design documentation These documentations contain all the necessary information which are needed to build the software It contains a High level software architecture b Software design details c Data flow diagrams d Database design These documents work as repository for developers to implement the software Though these documents do not give any details on how to code the program they give all necessary information that is required for coding and implementation 7 Software Engineering Tutorial Technical documentation These documentations are maintained by the developers and actual coders These documents as a whole represent information about the code While writing the code the programmers also mention objective of the code who wrote it where will it be required what it does and how it does what other resources the code uses etc The technical documentation increases the understanding between various programmers working on the same code It enhances re use capability of the code It makes debugging easy and traceable There are various automated tools available and some comes with the programming language itself For example java comes JavaDoc tool to gener
86. ntrol Change control is function of configuration management which ensures that all changes made to software system are consistent and made as per organizational rules and regulations A change in the configuration of product goes through following steps e Identification A change request arrives from either internal or external source When change request is identified formally it is properly documented e Validation Validity of the change request is checked and its handling procedure is confirmed e Analysis The impact of change request is analyzed in terms of schedule cost and required efforts Overall impact of the prospective change on system is analyzed 23 Software Engineering Tutorial e Control If the prospective change either impacts too many entities in the system or it is unavoidable it is mandatory to take approval of high authorities before change is incorporated into the system It is decided if the change is worth incorporation or not If it is not change request is refused formally e Execution If the previous phase determines to execute the change request this phase takes appropriate actions to execute the change through a thorough revision if necessary e Close request The change is verified for correct implementation and merging with the rest of the system This newly incorporated change in the software is documented properly and the request is formally closed Project Management Tools T
87. ogramming details than Structured English It provides a method to perform the task as if a computer is executing the code 48 Software Engineering Tutorial Example Program to print Fibonacci up to n numbers VOUS sie der ELLONE Get value of n Set value of a to 1 Set value of b to 1 Initialize T to 0 for i 0 i lt n i if a greater than b Increase b by a Print b I else if b greater than a 2 increase a by b print a Decision Tables A Decision table represents conditions and the respective actions to be taken to address them in a structured tabular format It is a powerful tool to debug and prevent errors It helps group similar information into a single table and then by combining tables it delivers easy and convenient decision making Creating Decision Table To create the decision table the developer must follow basic four steps e Identify all possible conditions to be addressed e Determine actions for all identified conditions e Create Maximum possible rules 49 Software Engineering Tutorial e Define action for each rule Decision Tables should be verified by end users and can lately be simplified by eliminating duplicate rules and actions Example Let us take a simple example of day to day problem with our Internet connectivity We begin by identifying all problems that can arise while starting the internet and their respective possible solutions We list all possible problems
88. on maintenance is analyzed and estimation is concluded Design New modules which need to be replaced or modified are designed against requirement specifications set in the previous stage Test cases are created for validation and verification Implementation The new modules are coded with the help of structured design created in the design step Every programmer is expected to do unit testing in parallel System Testing Integration testing is done among newly created modules Integration testing is also carried out between new modules and the system Finally the system is tested as a whole following regressive testing procedures Acceptance Testing After testing the system internally it is tested for acceptance with the help of users If at this state user complaints some issues they are addressed or noted to address in next iteration Delivery After acceptance test the system is deployed all over the Organization either by small update package or fresh installation of the system The final testing takes place at client end after the software is delivered Training facility is provided if required in addition to the hard copy of user manual Maintenance management Configuration management is an essential part of system maintenance It is aided with version control tools to control versions semi version or patch management Software Re engineering When we need to update the software to keep it to the current market
89. one Easy reversal of actions encourages exploration of unfamiliar options The units of reversibility may be a single action a data entry or a complete group of actions 65 Software Engineering Tutorial Support internal locus of control Experienced operators strongly desire the sense that they are in charge of the system and that the system responds to their actions Design the system to make users the initiators of actions rather than the responders Reduce short term memory load The limitation of human information processing in short term memory requires the displays to be kept simple multiple page displays to be consolidated window motion frequency be reduced and sufficient training time be allotted for codes mnemonics and sequences of actions 66 Software Engineering Tutorial Software Design Complexity The term complexity stands for state of events or things which have multiple interconnected links and highly complicated structures In software programming as the design of software is realized the number of elements and their interconnections gradually emerge to be huge which becomes too difficult to understand at once Software design complexity is difficult to assess without using complexity metrics and measures Let us see three important software complexity measures Halstead s Complexity Measures In 1977 Mr Maurice Howard Halstead introduced metrics to measure software complexity Halstead s metri
90. one diagram concealing all the underlying details Level 0 DFDs are also Known as context level DFDs Online Shopping System Aanleg Customers e Level 1 The Level O DFD is broken down into more specific Level 1 DFD Level 1 DFD depicts basic modules in the system and flow of data among various modules Level 1 DFD also mentions basic processes and sources of information 42 Software Engineering Tutorial Accounts Finance Verification _ gt Customer Data A Verify Processing Process Wel Issue tem Order Customers e Level 2 At this level DFD shows how data flows inside the modules mentioned in Level 1 Higher level DFDs can be transformed into more specific lower level DFDs with deeper level of understanding unless the desired level of specification is achieved Structure Charts Structure chart is a chart derived from Data Flow Diagram It represents the system in more detail than DFD It breaks down the entire system into lowest functional modules describes functions and sub functions of each module of the system to a greater detail than DFD Structure chart represents hierarchical structure of modules At each layer a specific task is performed Here are the symbols used in construction of structure charts e Module It represents process or subroutine or task A control module branches to more than one sub module Library Modules are re usable and invokable from any mo
91. ontrol management CASE tools help in this by automatic tracking version management and release management For example Fossil Git Accu REV 102 Software Engineering Tutorial Change Control Tools These tools are considered as a part of configuration management tools They deal with changes made to the software after its baseline is fixed or when the software is first released CASE tools automate change tracking file management code management and more It also helps in enforcing change policy of the organization Programming Tools These tools consist of programming environments like IDE Integrated Development Environment in built modules library and simulation tools These tools provide comprehensive aid in building software product and include features for simulation and testing For example Cscope to search code in C Eclipse Prototyping Tools Software prototype is simulated version of the intended software product Prototype provides initial look and feel of the product and simulates few aspect of actual product Prototyping CASE tools essentially come with graphical libraries They can create hardware independent user interfaces and design These tools help us to build rapid prototypes based on existing information In addition they provide simulation of software prototype For example Serena prototype composer Mockup Builder Web Development Tools These tools assist in designing web pages with all allied ele
92. ping cardinalities one to one one to many many to one many to many Data Dictionary Data dictionary is the centralized collection of information about data It stores meaning and origin of data its relationship with other data data format for usage etc Data dictionary has rigorous definitions of all names in order to facilitate user and software designers Data dictionary is often referenced as meta data data about data repository It is created along with DFD Data Flow Diagram model of software program and is expected to be updated whenever DFD is changed or updated Requirement of Data Dictionary The data is referenced via data dictionary while designing and implementing software Data dictionary removes any chances of ambiguity It helps keeping 51 Software Engineering Tutorial work of programmers and designers synchronized while using same object reference everywhere in the program Data dictionary provides a way of documentation for the complete database system in one place Validation of DFD is carried out using data dictionary Contents Data dictionary should contain information about the following e Data Flow e Data Structure e Data Elements e Data Stores e Data Processing Data Flow is described by means of DFDs as studied earlier and represented in algebraic form as described Composed of o Repetition Optional And Hy Or Example Address House No Street Area City Sta
93. pon the underlying hardware and software combination UI can be hardware or software or a combination of both The software becomes more popular if its user interface is e Attractive e Simple to use e Responsive in short time e Clear to understand e Consistent on all interfacing screens UI is broadly divided into two categories e Command Line Interface e Graphical User Interface Command Line Interface CLI CLI has been a great tool of interaction with computers until the video display monitors came into existence CLI is first choice of many technical users and programmers It is the minimum interface a software can provide to its users CLI provides a command prompt the place where the user types the command and feeds to the system The user needs to remember the syntax of command and its use Earlier CLI were not programmed to handle the user errors effectively 91 Software Engineering Tutorial A command is a text based reference to set of instructions which are expected to be executed by the system There are methods like macros scripts that make it easy for the user to operate CLI uses less amount of computer resource as compared to GUI CLI Elements Command an Pinaca lib gooalf ls al total 12264 drwxr xr x 21 gopal staf drowxr ar x 14 gopal staff gw t gd 1l gepal staff sw r s I gopal staff sw r r l gopal staff wer 1 1 gopal staff tw r 2 1 gopal staff sw r r i
94. presentation makes it easier for designers and managers to get the pictorial idea of the system structure Inventory Payment Authentication Check Prooess Dispatch Hem Generate Issue Item tem Missing Invoice Deduct Inventory In contrast to Input Process Output IPO diagram which depicts the flow of control and data in a module HIPO does not provide any information about data flow or control flow Authentication Input Process Output take authentication credentials from user screen User Screen ER Check validity of credentials User Screen Call Appropriate Module Example Both parts of HIPO diagram Hierarchical presentation and IPO Chart are used for structure designing of software program as well as documentation of the same 46 Software Engineering Tutorial Structured English Most programmers are unaware of the large picture of software so they only rely on what their managers tell them to do It is the responsibility of higher software management to provide accurate information to the programmers to develop accurate yet fast code Different methods which use graphs or diagrams at times might be interpreted in a different way by different people Hence analysts and designers of the software come up with tools such as Structured English It is nothing but the description of what is required to code and how to code it Structured English helps the programmer to write error free code
95. s next to impossible to remember the flow of program If one forgets how software and its underlying programs files procedures are constructed it then becomes very difficult to share debug and modify the program The solution to this is structured programming It encourages the developer to use subroutines and loops instead of using simple jumps in the code thereby bringing clarity in the code and improving its efficiency Structured programming also helps programmer to reduce coding time and organize code properly Structured programming states how the program shall be coded It uses three main concepts 1 Top down analysis A software is always made to perform some rational work This rational work is Known as problem in the software parlance Thus it is very important that we understand how to solve the problem Under top down analysis the problem is broken down into small pieces where each one has some significance Each problem is individually solved and steps are clearly stated about how to solve the problem 2 Modular Programming While programming the code is broken down into smaller group of instructions These groups are known as modules subprograms or subroutines Modular programming based on the understanding of top down analysis It discourages jumps using goto statements in the program which often makes the program flow non traceable Jumps are prohibited and modular format is encouraged in structured programmin
96. ses because of higher rate of change in user requirements and environment on which the software is working Following are some of the needs stated Large software It is easier to build a wall than a house or building likewise as the size of the software becomes large engineering has to step to give it a scientific process Scalability If the software process were not based on scientific and engineering concepts it would be easier to re create new software than to scale an existing one Cost As hardware industry has shown its skills and huge manufacturing has lower down the price of computer and electronic hardware But cost of the software remains high if proper process is not adapted Dynamic Nature Always growing and adapting nature of the software hugely depends upon the environment in which the user works If the nature of software is always changing new enhancements need to be done in the existing one This is where the software engineering plays a good role Quality Management Better process of software development provides better and quality software product Software Engineering Tutorial Characteristics of good software A software product can be judged by what it offers and how well it can be used This software must satisfy on the following grounds e Operational e Transitional e Maintenance Well engineered and crafted software is expected to have the following characteristics Operational This tells us
97. ses generation Following documents are needed for reference e SRS document Functional Requirements document e Test Policy document This describes how far testing should take place before releasing the product e Test Strategy document This mentions detail aspects of test team responsibility matrix and rights responsibility of test manager and test engineer e Traceability Matrix document This is SDLC document which is related to requirement gathering process As new requirements come they are added to this matrix These matrices help testers know the source of requirement They can be traced forward and backward While Being Tested The following documents may be required while testing is started and is being done e Test Case document This document contains list of tests required to be conducted It includes Unit test plan Integration test plan System test plan and Acceptance test plan e Test description This document is a detailed description of all test cases and procedures to execute them e Test case report This document contains test case report as a result of the test e Test logs This document contains test logs for every test case report After Testing The following documents may be generated after testing e Test summary This test summary is collective analysis of all test reports and logs It summarizes and concludes if the software is ready to be launched The software is released un
98. sion making constructs change the flow of the program If we compare two programs of same size the one with more decision making statements will be more complex as the control of program jumps frequently 68 Software Engineering Tutorial McCabe in 1976 proposed Cyclomatic Complexity Measure to quantify complexity of a given software It is graph driven model that is based on decision making constructs of program such as if else do while repeat until switch case and goto statements Process to make flow control graph e Break program in smaller blocks delimited by decision making constructs e Create nodes representing each of these nodes e Connect nodes as follows o If control can branch from block i to block j Draw an arc o From exit node to entry node Draw an arc To calculate Cyclomatic complexity of a program module we use the formula V G e n 2 Where e is total number of edges n is total number of nodes Code Flow Chart Flow Graph atatementl atatementl D If expressionl Btatement expressionl elge 8 SERE mts statement atatement3 Btatementd ET PRE a atatement4 ra ata tements t while expression Statement atatemantf expression atatamantf The Cyclomatic complexity of the above module is e 10 n 8 Cyclomatic Complexity 10 8 2 69 Software Engineering Tutorial 4 According to P Jorgensen Cyclomatic Complexity of a module should not exceed 10 Function Point It is
99. t are e Errors These are actual coding mistakes made by developers In addition there is a difference in output of software and desired output is considered as an error 91 Software Engineering Tutorial e Fault When error exists fault occurs A fault also known as a bug is a result of an error which can cause system to fail e Failure failure is said to be the inability of the system to perform the desired task Failure occurs when fault exists in the system Manual Vs Automated Testing Testing can either be done manually or using an automated testing tool e Manual This testing is performed without taking help of automated testing tools The software tester prepares test cases for different sections and levels of the code executes the tests and reports the result to the manager Manual testing is time and resource consuming The tester needs to confirm whether or not right test cases are used Major portion of testing involves manual testing e Automated This testing is a testing procedure done with aid of automated testing tools The limitations with manual testing can be overcome using automated test tools A test needs to check if a webpage can be opened in Internet Explorer This can be easily done with manual testing But to check if the web server can take the load of 1 million users it is quite impossible to test manually There are software and hardware tools which helps tester in conducting load testing
100. te Course ID Course Number Course Name Course Level Course Grades Data Elements Data elements consist of Name and descriptions of Data and Control Items Internal or External data stores etc with the following details e Primary Name e Secondary Name Alias e Use case How and where to use 52 Software Engineering Tutorial e Content Description Notation etc e Supplementary Information preset values constraints etc Data Store It stores the information from where the data enters into the system and exists out of the system The Data Store may include e Files o Internal to software o External to software but on the same machine o External to software and system located on different machine e Tables o Naming convention o Indexing property Data Processing There are two types of Data Processing e Logical As user sees it e Physical As software sees it 53 Software Engineering Tutorial Software Design Strategies Software design is a process to conceptualize the software requirements into software implementation Software design takes the user requirements as challenges and tries to find optimum solution While the software is being conceptualized a plan is chalked out to find the best possible design for implementing the intended solution There are multiple variants of software design Let us study them briefly Structured Design Structured design is a conceptualization of problem
101. tem Analysis d Testing A d Software ien p Integration t Design Testing K S Module Unit fa Ss Se a Design Testing F e s gt a gt Coding At every stage test plans and test cases are created to verify and validate the product according to the requirement of that stage For example in requirement gathering stage the test team prepares all the test cases in correspondence to the requirements Later when the product is developed and is ready for testing test cases of this stage verify the software against its validity towards requirements at this stage This makes both verification and validation go in parallel This model is also known as verification and validation model 13 Software Engineering Tutorial Big Bang Model This model is the simplest model in its form It reguires little planning lots of programming and lots of funds This model is conceptualized around the big bang of universe As scientists say that after big bang lots of galaxies planets and stars evolved just as an event Likewise if we put together lots of programming and funds you may achieve the best software product Time Efforts Software Resources For this model very small amount of planning is required It does not follow any process or at times the customer is not sure about the requirements and future needs So the input requirements are arbitrary This model is not suitable for large software projects but good one for learn
102. unday 5 January euteruguag aN ST Other impressive GUI components are e Sliders e Combo box e Data grid e Drop down list User Interface Design Activities There are a number of activities performed for designing user interface The process of GUI design and implementation is alike SDLC Any model can be used for GUI implementation among Waterfall Iterative or Spiral Model 62 Software Engineering Tutorial A model used for GUI design and development should fulfill these GUI specific steps GUI Requirement ed Specification User Analysis GUI Task Analysis GUI Design amp Implementation GUI Requirement Gathering The designers may like to have list of all functional and non functional requirements of GUI This can be taken from user and their existing software solution User Analysis The designer studies who is going to use the software GUI The target audience matters as the design details change according to the knowledge and competency level of the user If user is technical savvy advanced and complex GUI can be incorporated For a novice user more information is included on how to of software Task Analysis Designers have to analyze what task is to be done by the software solution Here in GUI it does not matter how it will be done Tasks can be represented in hierarchical manner taking one major task and dividing it further into smaller sub tasks Tasks provide goals for GUI presentation Flow of in
103. ur website or in this tutorial please notify us at contact tutorialspoint com Table of Contents SOFTWARE ENGINEERING TUTORIAL sessies sos de se Ge ee oe ee ed ese ge ede ee Ge Ge ee Ge se dee eg ge ee sede l AUDIENCE EE EE RE EE EANN E E OE l PREREQUISITES EE EE EA A O l COPYRIGHT Sc TSCA IVER E SOFTWARE e ATTEN 1 M ntel KE 1 SOET WARE EVOLUTION se ees oes ee ese E ee ee Ge ee ee GE Ge ee pe ie 2 SOFTWARE EVOLUTION LAWS ese ee ee ge ee ie Ge ie ee EE ee De ER Ee 3 BY E SOET WARE yO Ee 3 EE 4 Software Development ParadigM eeoeseneesnenoesernesreressereesreresseressreresseressreressereesrrresrereesrereseereee 4 Sotware Design POI OM ae RE de ED ie oe Ge GE cen EN ER Re EG RE 5 PRO OVO AG tee ee AE N OE EE EE N ON EO 5 NEED OF SOFTWARE ENGINEERING sies Sias eine ek ese see ae Sea os ie ee ee ie ie GE ee oe de ee ee ee GE N 5 CHARACTERISTICS OF GOOD oe RE OE EE N N 6 OT OOO EET EE OE EE OE EE N EE OE EE EE N 6 PIS sie lo EE EE EE EE EEN EE E ER ans EE EE EO EEN 6 Malh CC INTC sre EE EI EE EE EE EE OE EE N 6 SOFTWARE DEVELOPMENT LIFE CYCLE sesse siese ineen ee ee bees REG Ko de We Ge ee ee ee ee Geo GE ees ee 8 DES ep GE EE E EE TE EE 8 COMMUNIC O OI AO EE N EE EE EE EE OE OO OE OE Or 8 RENEE GADERING ee se ee Ge Oe Ge ee DE ed EO me de unde 8 arie Ie ES ie EE OE OE EE EE ED EE EE EE 9 EE 9 So Mare DES EE 9 CON EE N EO OE EE OE N OE 9 se ie EE N EE N EE EE N 9 ae ige aie RE ER EE OE EE OE RO EE OD N 10 Iimplemen a ON ecan
104. without impacting its functionality it is called software re engineering It is a thorough process where the design of software is changed and programs are re written 90 Software Engineering Tutorial Legacy software cannot keep tuning with the latest technology available in the market As the hardware become obsolete updating of software becomes a headache Even if software grows old with time its functionality does not For example initially Unix was developed in assembly language When language C came into existence Unix was re engineered in C because working in assembly language was difficult Other than this sometimes programmers notice that few parts of software need more maintenance than others and they also need re engineering Existing Reverse Software Engineering Re structuring Forward W Re engineered Engineering Software Re Engineering Process Decide what to re engineer Is it whole software or a part of it Perform Reverse Engineering in order to obtain specifications of existing software Restructure Program if required For example changing function oriented programs into object oriented programs Re structure data as required Apply Forward engineering concepts in order to get re engineered software There are few important terms used in Software re engineering 91 Software Engineering Tutorial Reverse Engineering It is a process to achieve system specification by t

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