SFC - Computer Science Department : Sonoma State University
Contents
1. Procedure or Function Typically programs are designed as a set of subroutines one of which is designated as the main subroutine When the program is executed execution begins with the first statement in the main subroutine The other subroutines in the program are called by the main subroutine and or by each other Subroutines can be divided into two categories functions and procedures A function returns a value to the calling subroutine a procedure does not Both functions and procedures can have information passed to them by the calling subroutine this is usually done by supplying a list of actual parameter values when the subroutine is called The formal descriptions of the parameter values expected by the subroutine are declared as part of the subroutine A new function or procedure can be inserted at a subroutine insertion point represented by a large shaded circle To insert a new function or procedure double click the left mouse button while pointing to the subroutine insertion point A dialog box will be displayed Enter Subroutine Information ES Enter procedure or function data Procedure No retum type Function with return type Function return value o Procedure or function name KA KA Parameter Name List EA Cancel 8 of 35 Inserting a New Procedure Enter the name of the new procedure and the list of parameter names in the dialog box and then left click on OK or press t2. the selected element is a control structure or subroutine selection will be indicated by a dashed line rectangle enclosing the complete structure or subroutine If the selected element is an insertion point selection will be indicated by a dashed line square enclosing the insertion point e Pointing to the symbol associated with a control structure subroutine or insertion point and double clicking the left mouse button will allow the user to modify the element If the element is a control structure or subroutine the appropriate text entry dialog box will be displayed If the element is an insertion point the appropriate insertion dialog box will be displayed The eft mouse button is also used to select a segment of the current pseudo code The right mouse button is used to display pop up menus e Pointing to the symbol associated with a control structure or subroutine and clicking the right mouse button will display a pop up menu with options to o Copy the control structure or subroutine to the clipboard o Cut the control structure or subroutine and place a copy on the clipboard o Delete the control structure or subroutine o Modify the control structure or subroutine o Transform the control structure e Pointing to an insertion point and clicking the right mouse button will display a pop up menu with options to o Insert a new control structure or subroutine at the insertion point o Paste a copy of the appropriate control structure or subrout
3. yes write Target value found in list else write Target value NOT found in list write Target value NOT found in list STOP Seq_Search 0 write Target value found in list 1 of 35 Example 2 Binary Search This example illustrates a function implementation of the Binary Search algorithm The flow chart its Generic style pseudo code and its C style pseudo code are shown START boolean BinarySearch integer value integers list test middle value in list found BinarySearch value list values preceding test STOP return found found BinarySearch value list values following test 2 of 35 Generic Style Pseudo Code FUNCTION BinarySearch integer value integers list RETURNING boolean BEGIN BinarySearch IF list contains one value THEN IF value equal only value in list THEN found true ELSE found false END IF ELSE test middle value in list IF value equal test value THEN found true ELSE IF value less than test value THEN found BinarySearch value list values preceding test ELSE found BinarySearch value ist values following test END IF END IF END IF RETURN found END BinarySearch C Style Pseudo Code boolean BinarySearch integer value integers list if list contains one value if value equal only value i
4. Get_s maller Enter list of parameter values value _ value carcel_ After entering the statement associated with the subroutine call statement in the dialog box left click on OK or press the Enter key The new subroutine call symbol and its contents will then be displayed in the flow chart de sfe Stel Piel Es File Edit View Window Help laj x Deh 28 2 Sample Program Sample Program Author Author Get_Smaller valuel value2 value value2 Get_Smaller Ready NUM di 14 of 35 d Single Decision The decision symbol is used to represent a comparison question test selection or decision that determines an alternative path to be followed The single branch decision structure has a control structure insertion point only on the True T branch of the decision symbol Control structures placed on the True branch of a single decision structure are only executed if the test enclosed in the decision symbol is true If the result of the test is false the structures on the True branch are by passed After selecting the single decision option a dialogue box for entering the contents of the decision symbol will be displayed Dialog ES A single branch decision statement will execute its THEN clause when the condition is true Enter condition vi gt 10 T T Select format F fe Cancel After entering the condition associated with the single branch decision stat
5. S Cancel After entering the condition associated with the test at the bottom looping statement in the dialog box left click on OK or press the Enter key The new loop decision symbol and its contents and a entry flow line containing a single structure insertion point will then be displayed in the flow chart de sfe Sfcl Jo x File Edit View Window Help OSES Be Q 27 BSc a Program Name f Author Author Program Name do while there are no more values to read there are 7 no more values to read NUM gt 2 20 of 35 j Counting Loop The counting loop performs body of the loop once for each desired value of the loop control variable When the value of the loop control variable is outside of the indicated bounds iterative execution of the body of the loop will be terminated In some cases the body of a counting loop may not be executed at all After selecting the counting loop option a dialogue box for entering the contents of the loop header symbol will be displayed Counting Loop Information FE Counting Loop Information ES Loop Type icy Increasing Decreasing Loop Type o Increasing Loop Control Variable Loop Control Variable Starting Value Starting Value Step Value Step Value po Ending Value fio Ending Value fo z Cancel Cancel After entering the loop control variable and the desired starting ending and step values in the dialog left cl
6. SFC A Structured Flow Chart Editor Version 2 3 User s Guide Tia Watts Ph D Sonoma State University 1 of 35 SFC A Structured Flow Chart Editor Version 2 3 User s Guide Table of Contents EOD UI CUO I spec O tl taaeateashnns Si aE Getting Started with SPC incinen ii a E E nuendesvsndcceusseesades lastaceessseaae Th SPC Environment tuto ii SEa do ota Creating a New Structured Flow Chtt es Opening an Existing Structured Flow Chart oooooonnnnccnnnncccnoncccnnncncnoncnonnnnccnnncnonnncconnncnos Inserting a Now Proteina Inserting Control STTUCTUTES 1 A A E AAA A Sequential Process Or CUY ie aria A a gata AR E E E dead E AEA EE EES Subroutine Calla li E Double Decio A A A E AA RA DT Case Statement isiin iiss Ene ld bid Caso Option a tas cada easy aos sanas Testat the Top Loop a asus Testat the BOO LOOP e A a a aR Countino LOOP artesania tn User Controlled Exit Loop usina nidad ts tesedata eras canada secas 8 Inserta Documenta ences yurecase goetucsde go actue dias tesesgucars EE N E NERES iE 9 Modifying Control Structure ti ast ont oleae E nate catered meuditone a 10 Transforming Control Structures 20 0 0 cee eeeesceceencecesececeeeeeceeeeeceeeeceneecseeecseeecneeeesaeees 11 Using Cut Copy And Pastora oido iia catan 12 Printing a Structured Flow Chart A A A A A ee 13 Viewing and Printing Pseudo Code lui octal eee e iinet ete cee mea 14 Saving a Structured Plow Chito 15 Closing a Structured Flow Ch
7. added to a program subroutine insertion points will be placed before and after the new function ee sfe Sfc1 Iof xi File Edit View Window Help e xj OS iBBa 2 Sample Program gt Sample Program O Author int Get_Smaller int v1 int v2 START return smaller int Get_Smaller int v1 int v2 STOP return smaller 10 of 35 7 Inserting Control Structures Control structures are inserted by double clicking the left mouse button while pointing to a control structure insertion point The control structure insertion points are represented as small shaded circles on the control flow lines of a procedure On some screens control structure insertion point circles may actually appear as small shaded diamonds When the left mouse button is double clicked a control structure insertion dialog box will be displayed The type of control structure is determined by left clicking on the appropriate radio button After selecting the control structure type left click on OK or press the enter key A dialog box for the selected control structure type will be displayed After a new control structure is inserted in a procedure control structure insertion points will be placed before and after the new structure This dialog box will also be used when adding documenting comments to a flow chart Insert New Control Structure or Comment ES Sequential Control Structures esaevencensarssnvtesensensorsegvesaunevensensenusasherebennss
8. alse OK N I T F Branch branches branches branches branch branch branch branches lost lost lost lost lost lost lost Selection All All All First First N A First First First N A All branches branches branches branch default branch branch default branches lost lost lost kept kept kept kept kept lost Test at Top Loop Loop Loop body OK OK OK N A OK OK N I Loop body lost body lost lost body lost Test at Loop Loop Loop body OK OK OK OK N A OK N I Loop Bottom body lost body lost lost Loop body lost body lost User Pre post Pre post Pre post Post exit OK OK Post exit Post exit N A N I Pre post Controlled exit body exit body exit body body body body exit body lost lost lost lost lost lost lost Counting N I N I N I N I N I NT NA N I N I NA NA Comment OK OK OK OK OK OK OK OK OK N I N A 25 of 35 11 Using Cut Copy and Paste to Modify Flow Charts Cut copy and paste can be used to remove move or duplicate control structures functions and procedures in a flow chart To select the control structure procedure or insertion point that will be the target of the cut past or copy command point to the structure symbol and click the left mouse button The current selected component will be outlined with a dashed line box in the flow chart If the selected component is a control structure the text associated with the structure will be highlighted in the pseudo code Le
9. art View ini cn beicon 16 Exporting SVG and TXT AES a A eh 17 Editing Multiple Structured Flow Charts uti ee eee eee le 18 Exiting from SEC ur i Appendix A Flow Chart Symbols miii a id Appendix Be Example tp a A A PON OR ror mo ae of Software and Documentation Copyright Tia Watts 2001 2 of 35 1 Introduction Program development can be described as a seven step process Understand the problem Plan the logic of the program Code the program using a structured high level computer language Using a compiler translate the program into a machine language Test and debug the program Put the program into production Maintain and enhance the program ANA A NS Planning the logic of the program requires the development of algorithms An algorithm is a finite ordered set of unambiguous steps that terminates with a solution to the problem Human readable representations such as flow charts and pseudo code are typically used to describe the steps of an algorithm and the relationships among the steps A flow chart is a graphical representation of the steps and control structures used in an algorithm A flow chart does not involve a particular programming language but rather uses a set of geometric symbols and flow control lines to describe the algorithm From a flowchart a programmer can produce the high level code required to compile an executable program Initially the standard for describing flow charts only specified
10. de will be automatically generated for a Structured Flow Chart as it is being created To select the Pseudo Code Style Select the C Style option on the View menu default OR Select the Generic Style option on the View menu 28 of 35 ETS Bm ES File Edit View Window Help la x de sfc ss22 A ES File Edit View Window Help lej xj Deua Be 2 Sample Program oid Seq_Search read target value TY let FOUND no while values in list and FOUND no OSHS tte ROGRAM Sample Program UTHOR Author OURSE ROCEDURE Seq_Search f EGIN Seq_ Search read target value TY let FOUND no WHILE values in list and FOUND no DO read value from list LY read value from list LV IF TY LY THEN if T LY let FOUND yes let FOUND yes END IF END WHILE if FOUND yes write Target value found in list else write Target value NOT found in list a NUM y IF FOUND yes THEN write Target value found in list ELSE write Target value NOT found in list END IF Ready Ready To preview the printed Pseudo Code After left clicking in the pseudo code frame Select the Print Preview option on the File menu The printed version of the pseudo code will be displayed To print the pseudo code After left clicking in the pseudo code frame Select the Print option on the File menu OR Click on the printer icon on the tool bar 14 Savi
11. ement in the dialog box left click on OK or press the Enter key The new decision symbol its condition and a true branch containing a single structure insertion point will then be displayed in the flow chart ee sfc Sfcl Aa x File Edit View Window Help ASHES shen 2 Program Name Author Author if 1 gt 10 NMI z 15 of 35 e Double Decision The double branch decision structure has control structure insertion points on both the True T and False F branches of the decision symbol Only one path will be followed after the test enclosed in the decision symbol is evaluated After selecting the double decision option a dialogue box for entering the contents of the decision symbol will be displayed Text Entry Form ES amp dual decision will execute its THEN branch when its condition is true and its ELSE branch when false Enter condition V1 gt 10 TAE FAT Select format a Cancel After entering the condition associated with the double branch decision statement in the dialog box left click on OK or press the Enter key The new decision symbol its condition and true and false branches each containing a single structure insertion point will then be displayed in the flow chart de sfe Sfcl 01 x File Edit View Window Help OSHS telal Program Name Author Program Name if 1 gt 10 else 16 of 35 f Case Statements The case or mu
12. genarey Input or Output READ or WRITE C Call Procedure or Function Decision Control Structures Single Decision IF THEN Double Decision IF THEN ELSE C Selection SELECT CASE Iterative Control Structures C TestatTopLoop WHILE DO Test at Bottom Loop REPEAT WHILE Counting Loop FOR NEXT C User Controlled Exit Loop WHILE TRUE 1F Documentation C Comment Cancel The following sections describe each of the types of control structures that can be added to the flow chart 11 of 35 a Sequential Processes or Activity The Sequential Process symbol is used to represent calculations processes and other unambiguous actions After selecting the sequential process option of the insert new control structure dialogue box and left clicking on OK or pressing the Enter key a dialogue box for entering the contents of the sequential process symbol will be displayed Text Entry Form FS Sequential statements are used to perform unambiquous actions or expressions Enter expression fet variable 1 0 caca After entering the statement associated with the sequential process in the dialog box left click on OK or press the Enter key The new sequential process symbol and its contents will then be displayed in the flow chart de sfe Sfc1 Al ES File Edit View window Help la xj DEHA e 2 Sample Program Program Sample Pro
13. gram Author Author let variable 1 0 let variable 1 0 Ready NUM di 12 of 35 b Input or Output The Input or Output symbol is used to represent input read or output write statements After selecting the input or output option a dialogue box for entering the contents of the input output symbol will be displayed Text Entry Form ES Input Output statements should be used to READ data values or to WRITE result values Enter expression read value into 41 After entering the statement associated with the input output statement in the dialog box left click on OK or press the Enter key The new input output symbol and its contents will then be displayed in the flow chart de sfe Sfc1 Al ES File Edit View Window Help 5 xj Dendes sea Sample Program Sample Program ie Author K read value into 1 read value write value of 1 into 1 write value of v1 13 of 35 c Subroutine Call The Subroutine Call symbol is used to represent execution of a predefined process or group of processes The name of the subroutine and values to be passed to the subroutine should be enclosed within the subroutine call symbol After selecting the subroutine call option a dialogue box for entering the contents of the subroutine call symbol will be displayed Text Entry Form ES A stand alone call statement will activate execution of a procedure Enter procedure name
14. he enter key Enter Subroutine Information Fe Enter procedure or function data Function with return type Function return value AA Procedure or function name Prints ummary Parameter Name List fint page_number Coreei Initially the new procedure consists of START and STOP labels and a control structure insertion point In addition when a new procedure is added to a program subroutine insertion points will be placed before and after the new procedure de sfe Sfc1 Pile Es File Edit View Window Help e xj Oe 308 2 Sample Program a 9 Sample Program Author oid Print_ Summary int page_number START Print_Summary int page _number STOP Print_Summary int page_number 9 of 35 Inserting a New Function Enter the name of the new procedure and the list of parameter names in the dialog box In addition the value to be returned and its type should be entered in the dialog box before left clicking on OK or pressing the enter key Enter Subroutine Information ES Enter procedure or function data Procedure No return type Function return value smaller Procedure or function name Get Smaller Parameter Name List fint y1 int y2 Cancel Initially the new function consists of START and STOP labels and a control structure insertion point The return value will be indicated in the STOP label In addition when a new function is
15. ick on OK or press the Enter key The new loop header symbol its contents and a true branch containing a single structure insertion point will then be displayed in the flow chart S sfe Stel BEE He ste ELGA Biel ES File Edit View Window Help la x EJ File Edt View Window Help l xj EHS tr Deol 2e8 Sample Program Author Sample Program Sample Program Author o START main Q Sample Program START main for 1 1 Y1 lt 10 1 1 1 for 1 1 Y1 gt 10 1 1 1 21 of 35 k User Controlled Exit Loop The User Controlled Exit Loop performs body of the loop until the exit condition is true As long as the test result is false the body of the loop will continue to be executed In some cases the portion of the loop body following the exit test may not be executed at all After selecting the user controlled exit loop option a dialogue box for entering the contents of the loop decision symbol will be displayed Text Entry Form Ea A User Controlled Exit loop will loop until an exiting statement is executed in the body of the loop Enter condition fat end of input data Select format g 2 gt E E cores After entering the condition associated with the user looping statement in the dialog box and selecting the desired format left click on OK or press the Enter key The new loop decision symbol it
16. ine on the clipboard at the insertion point 6 of 35 4 Creating a New Structured Flow Chart To create a new structured flow chart Click on the word File in the main SFC menu bar Select the New option in the file menu OR Click on the blank page icon in the SFC tool bar A New Program dialog box will be displayed Use this dialog box to name the program and identify yourself as the author Program Identification Information E The new flow chart displayed on the left side of the screen consists of a procedure called main and two subroutine insertion points the large shaded circles The main subroutine a procedure is identified by START and STOP labels and contains a single control structure insertion point the small shaded circle on the control flow lines between START and STOP Read only pseudo code for the main procedure is displayed on the right side of the screen fie sfe Sfc1 OP x EJ File Edit View Window Help l x Dwell Se Sample Program Auber eles Program Course oid main A Hag RaZ 7 of 35 5 Opening an Existing Structured Flow Chart To open and edit a saved structured flow chart Select the Open option in the file menu Select or enter the name of the file Click on OK or press the enter key OR Click on the open folder icon in the SFC tool bar Select or enter the name of the file Click on OK or press the enter key 6 Inserting a New Subroutine
17. ion label 2 cancel After entering the value associated with the case option in the dialog box left click on OK or press the Enter key The new option decision symbol its value and a path containing a single structure insertion point will then be displayed in the flow chart de sfe Sel Pale ES File Edit View window Help lej x OSHS tme 2 Sample Program hater pelos Program Course switch value of 1 case 2 break O rie Ready NUM Yi 18 of 35 h Test at the Top Loop Looping or iterative structures are used to represent repetitive actions The loop control symbol contains a comparison question test or decision that determines which branch of the loop will be executed Initially the true branch of the loop contains a control structure insertion point Control structures inserted on the true branch of the loop comprise the body of the loop The Test at the Top Loop performs the test prior to executing the body of the loop As long as the test result is true the body of the loop will continue to be executed If the result of the test is false iterative execution of the body of the loop will be terminated In some cases the body of a test at the top loop may not be executed at all After selecting the test at the top loop option a dialogue box for entering the contents of the loop decision symbol will be displayed Text Entry Form xi A test at the top loop wi
18. ll test its condition and will iterate as long as the condition is true Enter condition there are no more values to read 3 fa O Oy Select format After entering the condition associated with the test at the top looping statement in the dialog box and selecting the desired format left click on OK or press the Enter key The new loop decision symbol its contents and a true branch containing a single structure insertion point will then be displayed in the flow chart J sfe Sfel Jol x File Edit View Window Help Oeus elol e jW Program Program Name Author Program Name while there are no more values to read there are no more values to read 19 of 35 i Test at the Bottom Loop The Test at the Bottom Loop performs the test after executing the body of the loop As long as the result of the test is true the body of the loop will continue to be executed If the result of the test is false iterative execution of the body of the loop will be terminated The body of a test at the bottom loop will always be executed at least one time After selecting the test at the bottom loop option a dialogue box for entering the contents of the loop decision symbol will be displayed Text Entry Form Ea A test at the bottom loop will execute the statements in its body once and will iterate while the condition is true Enter condition there are no more values to read Select format R3 C E
19. lti branch decision structure has insertion points for case option statements and a default branch Only one path will be followed after the statement enclosed in the decision symbol is evaluated After selecting the case statement option a dialogue box for entering the contents of the case selection statement will be displayed Text Entry Form EE A selection will execute the appropriate option when it matches the condition and its DEFAULT branch other Enter selection condition value ofl caca After entering the statement associated with the case statement in the dialog box left click on OK or press the Enter key The new case symbol its selection statement and case option and default branches will then be displayed in the flow chart ee sfc Sfe1 Al x File Edit View window Help lej x 0d e 2 Program Sample Program Author Author Course Sample Program oid main switch value of 1 Ready NUM Yi 17 of 35 g Case Options The double branch decision structure has control structure insertion points on both the True T and False F branches of the decision symbol Only one path will be followed after the test enclosed in the decision symbol is evaluated After double clicking the left button on a case option insertion point a dialogue box for entering the contents of the option decision symbol label will be displayed Text Entry Form x Enter opt
20. n list found true else found false else test middle value in list if value equal test value found true else if value less than test value found BinarySearch value list values preceding test else found BinarySearch value list values following test return found 2 of 35
21. n using the format Generic or C selected from the View menu To save a structured flow chart as a text file Select the ExportAs option on the File menu Select Text Files txt as the Save as type Click on a file name or enter a new name in the dialog box Click on the OK button or press the enter key 30 of 35 17 Editing Multiple Structured Flow Charts Using multiple windows two ore more flow charts can be edited at the same time Follow the instructions in sections 4 or 5 to open a second new or existing flow chart To view multiple flow charts one above the other Select the Tile option on the windows menu de sfc SeqSearchP iof x File Edit View Window Help Demer 12 RE SeqSearchF ajy P ES le Pr 1 Sample Program 1 r a pies ogam Course START bool Seq_Search ch TV li a reas Seq_Search TV list let FOUND no while values in list and FOUND no e read value from list LV BE SeqSearchP spero a ea Course START was ie oid Seq_Search J read target value TV let FOUND no while values in list and FOUND no Control structures or procedures cut or copied from one structured flow chart can be pasted to the appropriate type of insertion point in another flow chart 18 Exiting from SFC To exit from SFC Left click on the X button on the upper right corner of the SCF main window OR Select the Exit option in the File menu 31 of 35 Appendix A Flo
22. ng a Structured Flow Chart A structured flow chart can be saved as a file on a disk To save a structured flow chart Select the Save option on the File menu OR Click on the disk icon on the tool bar To save a structured flow chart using a different name Select the SaveAs option on the File menu Click on a file name or enter a new name in the dialog box Click on the OK button or press the enter key 29 of 35 15 Closing a Structured Flow Chart View To close a structure flow chart view window Select the Close option on the File menu OR Click on the X button in the upper right corner of the structured flow chart view frame 16 Exporting SVG and TXT files The ExportAs option of the File menu can be used to create Scalable Vector Graphics svg or text txt files Scalable Vector Graphics SVG is a graphics format designed by Adobe and based on XML SVG files can be viewed using the Adobe SVG Viewer SVG files can be incorporated into web pages Since SVG files are text files they can be modified using a text editor To save a structured flow chart as an SVG file Select the ExportAs option on the File menu Select Scalable Vector Graphic Files svg as the Save as type Click on a file name or enter a new name in the dialog box Click on the OK button or press the enter key The pseudo code associated with a flow chart can be exported to a text file for further editing or compiling The pseudo code file will be writte
23. nt SFC flow chart to the clipboard Copy the selected pseudo code from the current SFC pseudo code view to the clipboard Paste the flow chart element stored on the clipboard into the selected insertion point in the current SFC flow chart e Insert a new flow chart element at the selected insertion point in the current SFC flow chart Modify the selected control structure or subroutine in the current SFC flow chart e Transform the selected control structure in the current SFC flow chart to another control structure 5 of 35 The View menu includes options allowing the user to View or hide the Tool Bar View or hide the Status Bar Select the Generic style of pseudo code for the current SFC flow chart Select the C style of pseudo code for the current SFC flow chart Include line numbers in the pseudo code window The Window menu includes options allowing the user to Create a copy of the current SFC flow chart in a new window Display a cascade of the open SFC flow chart documents Display a horizontal tiling of the open SFC flow chart documents View and select from a list of the open SFC flow chart documents The Help menu includes options allowing the user to e View SFC version information The left mouse button is used to select or modify an element in the current SFC flow chart e Pointing to the symbol associated with a control structure subroutine or insertion point and single clicking the left mouse button will select the element If
24. or copy command will be inserted at the selected control structure insertion point If a subroutine insertion point has been selected a copy of the subroutine most recently placed on the clipboard by a cut or copy command will be inserted at the selected subroutine insertion point If a case option insertion point has been selected a copy of the case option most recently placed on the clipboard by a cut or copy command will be inserted at the selected case option insertion point Copying Flow Chart or Pseudo Code Statements into Other Applications Segments of a flow chart can be copied and pasted as figures to word processing drawing presentation graphics and other applications by selecting the segment using the SFC Edit Copy command to copy the graphic to the system clip board and pasting it into the other application Similarly segments of pseudo code can be copied and pasted as text into other applications 27 of 35 12 Printing a Structured Flow Chart To preview a printed Structured Flow Chart Select the Print Preview option on the File menu The printed version of the flow chart will be displayed Each procedure will be displayed on a separate page Each procedure is scaled to fit within the margins of an 8 Ya by 11 page AO aa a kapal 200 To print a Structured Flow Chart Select the Print option on the File menu OR Click on the printer icon on the tool bar 13 Viewing and Printing Pseudo Code Pseudo co
25. pplicable select a format for the new structure The new structure will replace the original structure in the flowchart 24 of 35 In some cases flow chart structures will be lost when a transformation is performed For example in the following example where a double decision structure is transformed into a single decision structure the false branch is lost Transform Double Branch Decision Control Eg Sequential Control Structures C Sequential Process Activity Input or Output READ or WRITE Call Procedure or Function Decision Control Structures sk f Selection SELECT CASE Iterative Control Structures TestatTop Loop WHILE DO Test at Bottom Loop REPEAT WHILE User Controlled Exit Loop WHILE TRUE IF Documentation Comment Cancel The following table describes the actions performed when a structure is transformed to a different structure N A Not applicable N I Not implemented From To Seq T O Call Single Double Sel Top Bottom User Count Com Sequential N A OK OK OK OK OK OK OK OK N I OK Input or OK N A OK OK OK OK OK OK OK N I OK Output Subroutine OK OK N A OK OK OK OK OK OK N I OK Call Single True True True N A OK OK OK OK OK N I True Branch branch branch branch lost branch lost lost lost Double T F T F T F False N A OK False F
26. s contents and a path containing a structures insertion points before and after the exit condition will then be displayed in the flow chart de sfe Stel A x File Edit View window Help lej xj 0SdeSlBBa Program Name Program Name Author while true if at end of input data break at end of input data 22 of 35 8 Inserting Documentation Documentation can be added to a flow chart at structure insertion points Double click on the insertion point to display the control structure dialog box After selecting the comment option a dialogue box for entering the contents of the comment will be displayed Comment Entry Form Fe Enter comment Exit from this loop at end of input data Select format Cancel After entering the comment in the dialog box and selecting the desired format left click on OK or press the Enter key The new comment will then be displayed in the flow chart in a dashed box to the left or right of the line of flow of the flow chart structure de sfe Sfc1 Iof x File Edit View window Help e xj DER trena a Program Name Author Author Course i Exit from this i op is of i lamab y inputdata i PRA il Exit from this loop at end of input data while not end of file Ready NUM Wi 23 of 35 9 Modifying Control Structures The contents of a control structure can be modified by double clicking the left mouse button while pointing
27. sfe Sfc1 ol File Edit View Window Help laj xj Ose tser i Sample Program Author hile more data to be read if key value is odd add key to odd total else add key to even total To cut a control structure Select the structure by left clicking on the symbol representing the structure Then Select the cut option in the edit menu OR Click on the scissors icon in the tool bar OR Right click on the structure and select the cut option in the pop up menu 26 of 35 The control structure will be removed from the flow chart and placed on the control structure clipboard To copy a control structure Select the structure by left clicking on the symbol representing the structure Then Select the copy option in the edit menu OR Click on the duplicate icon in the tool bar OR Right click on the structure and select the copy option in the pop up menu A copy of the control structure will be placed on the control structure clipboard To paste a control structure Select an insertion point by left clicking on the small shaded circle representing the control structure insertion point Then Select the copy option in the edit menu OR Click on the paste from clipboard icon on the tool bar OR Right click on the insertion point and select the paste option in the pop up menu If a control structure insertion point has been selected a copy of the control structure most recently placed on the clipboard by a cut
28. the Run option Enter c sfc in the Run dialog box and click on OK or press the enter key Once you have started the SFC program the main window will be displayed NUM Tg Using the left mouse button click on OK to proceed You can maximize the size of this window by clicking on the full screen button in the upper right corner of the window frame 4 of 35 3 The SFC Environment Minimize Maximize Exit Menu Bar E File Edit View Window Help xj Tool Bar AY ETE CEA Program Name Status Bar NNI y Create Open Save Print Cut Copy Paste Undo Zoom Zoom Help New Exist Chart In Out Flow ing to Chart Chart Disk The File menu includes options allowing the user to Create a new SFC flow chart document Open an existing SFC flow chart document Save the current SFC flow chart document to a file Save the current SFC flow chart document to a newly named file Export the current SFC flow chart to an SVG or TXT file Print the current SFC flow chart or pseudo code view Preview the print version of the current SFC flow chart or pseudo code view Set the printing parameters View and select from a list of recent SFC flow chart documents Exit from the SFC Editor The Edit menu includes options allowing the user to e Undo the most recent modification made to the current SFC flow chart Cut the selected control structure or subroutine from the current SFC flow chart Copy the selected flow chart element from the curre
29. the types of shapes and lines used to produce a flow chart The introduction of structured programming in the 1960 s and 70 s brought with 1t the concept of Structured Flow Charts In addition to a standard set of symbols structured flow charts specify conventions for linking the symbols together into a complete flow chart The structured programming paradigm evolved from the mathematically proven concept that all problems can be solved using only three types of control structures Sequence Decision or Selection Iterative or looping The definition of structured flow charts used in this document and software further defines 3 types of sequential structures Process Input Output and Subroutine Call 3 types of decision structures Single Branch Double Branch and Case 4 types of iterative structures Test at the Top Test at the Bottom Counting and User Controlled Exit The SFC program is designed to aid the programmer in designing and presenting structured flow charts In addition SFC will automatically generate pseudo code for a flow chart as the flow chart is being created 3 of 35 2 Getting Started with SFC To start the SFC program Place the disk containing the SCF program in the A drive From the Start menu select the Run option Enter a sfc in the Run dialog box and click on OK or press the enter key OR if you have copied the SFC program onto the hard drive C of your computer From the Start menu select
30. to the symbol representing the control structure The current contents will be displayed in the appropriate dialog box After the contents have been modified click on OK or press the enter key to save the modification The modified structure will be displayed in the flow chart 10 Transforming Control Structures The transform option can be used to change the type of a control structure For example a single branch decision structure can be changed to a dual branch decision or a test at the top loop can be changed to a test at the bottom loop To transform a control structure Select the structure by left clicking on the symbol representing the structure Then Select the transform option in the edit menu OR Right click on the structure and select the transform option in the pop up menu Select the desired structure and click on OK Single Branch Decision Control Structure x Sequential Control Structures C Sequential Process Activity C Input or Output READ or WRITE C Call Procedure or Function Decision Control Structures Aad Selection SELECT CASE Iterative Control Structures TestatTopLoop WHILE DO C Test atBottomLoop REPEAT WHILE User Controlled Exit Loop WHILE TRUE IF Documentation Before After C Comment Cancel The text entry dialog box for the new structure will be displayed so that you may verify the textual contents of the structure and if a
31. w Chart Symbols Subroutine START STOP with Control Structure Insertion Point Comment 2 formats Sequential Process or Activity Input or Output Subroutine Call Single Branch Decision 2 formats Double Branch Decision 2 formats Case Statement with Case Option F Ke F T T F F Test at Top Loop 4 formats Oo Test at Bottom Loop 2 formats Counting Loop User Controlled Exit Loop 4 formats 32 of 35 Appendix B Examples Example 1 Sequential Search This example illustrates a procedure implementation of the Sequential Search algorithm The flow chart its Generic style pseudo code and its C style pseudo code are shown Flow Chart Generic Style Pseudo Code START Seq_Search 0 PROCEDURE Seq_Search BEGIN Seq_Search read target value TV let FOUND no WHILE values in list and FOUND no DO read value from list LV IF TV LV THEN let FOUND yes END IF END WHILE IF FOUND yes THE write Target value found in list read target value TW Z ELSE values in list and FOUND no write Target value NOT found in list END IF read value from list Lv END Seq_Search C Style Pseudo Code void Seq_Search read target value TV let FOUND no while values in list and FOUND no read value from list LV if TV LV let FOUND yes if FOUND
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