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6-1 COBOL for the 21 st Century Nancy Stern Hofstra University Robert A. Stern Nassau Community College James P. Ley University of Wisconsin-Stout (Emeritus)

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Presentation on theme: "6-1 COBOL for the 21 st Century Nancy Stern Hofstra University Robert A. Stern Nassau Community College James P. Ley University of Wisconsin-Stout (Emeritus)"— Presentation transcript:

1 6-1 COBOL for the 21 st Century Nancy Stern Hofstra University Robert A. Stern Nassau Community College James P. Ley University of Wisconsin-Stout (Emeritus) John Wiley & Sons, Inc. 11th edition

2 6-2 Moving Data, Printing Information, and Displaying Output Interactively Chapter 6

3 6-3 Chapter Objectives To familiarize you with Options of MOVE statement Rules for moving fields and literals Printing edit symbols Designing and printing reports

4 6-4 Chapter Contents Instructions formats of MOVE statement Numeric MOVE Nonnumeric or alphanumeric MOVE Other options of MOVE statement Producing printed output and screen displays Displaying output interactively using screen input and output

5 6-5 Humor

6 6-6 MOVE Statement MOVE identifier-1 TO identifier-2 Copies contents of identifier-1 To identifier-2 identifier-1 is sending field identifier-2 is receiving field FORMAT 1

7 6-7 MOVE Statement Example Move Qty-In To Qty-Out Contents of Qty-Out replaced by contents of Qty-In If Qty-In = 253, contents of Qty-Out = 253 after MOVE executed Qty-In remains unchanged Example

8 6-8 MOVE Statement MOVE literal-1 TO identifier-2 Value of literal-1 copied to identifier-2 Data type of literal and identifier should match –Move numeric literals to numeric fields –Move nonnumeric literals to alphanumeric fields FORMAT 2

9 6-9 MOVE Statement Examples 05 Qty-Out Pic Color-Out Pic X(4). Move 100 To Qty-Out Move 'Blue' To Color-Out Contents of Qty-Out replaced with 100 Contents of Color-Out replaced with 'Blue' Examples

10 6-10 Multiple Moves MOVE identifier-1 TO identifier-2 … literal-1 Move 0 To Total-1, Total-2, Total-3 Move may have multiple receiving fields Contents of all three total fields set to 0 Full Format

11 6-11 Moving Figurative Constants ZEROS may be moved to numeric or alphanumeric field –Moves 0 to every position of receiving field SPACES moved only to alphanumeric field –Moves space or blank to every position of receiving field

12 6-12 Numeric MOVE Numeric field or literal is moved to numeric receiving field When PIC clauses of both fields identical, sending and receiving fields same after MOVE Previous contents of receiving field are replaced by MOVE

13 6-13 Numeric MOVE Rules Decimal alignment always maintained –If is moved to a field 86 always treated as integer part of number.52 always treated as decimal part of number Digits in integer part moved right to left starting at decimal point Digits in decimal part moved left to right starting at decimal point

14 6-14 Numeric MOVE Example Operation: Move Amt-1 To Amt-2 Amt-1 Amt-2 Picture 99V99Picture 99V99 Contents 12 ^ 34Contents 67 ^ 89 Digits in integer part moved so that –2 replaces 7, 1 replaces 6 Digits in decimal part moved so that –3 replaces 8, 4 replaces 9

15 6-15 Numeric MOVE Example Operation: Move Amt-1 To Amt-2 Amt-1 Amt-2 Picture 99V99Picture 99V99 Contents 12 ^ 34Contents 67 ^ 89 After MOVE, contents of Amt-2 = 12 ^ 34

16 6-16 Numeric MOVE Rules If receiving field has more integer positions than sending field –Unfilled high-order (leftmost) integer positions filled with zeros If receiving field has more decimal positions than sending field –Unfilled low-order (rightmost) decimal positions filled with zeros

17 6-17 Numeric MOVE Example Operation: Move Amt-3 To Amt-4 Amt-3 Amt-4 Picture 9V9Picture 99V99 Contents 3 ^ 4Contents 56 ^ 78 Digits in integer part moved so that –3 replaces 6, 0 replaces 5 Digits in decimal part moved so that –4 replaces 7, 0 replaces 8

18 6-18 Numeric MOVE Example Operation: Move Amt-3 To Amt-4 Amt-3 Amt-4 Picture 9V9Picture 99V99 Contents 3 ^ 4Contents 56 ^ 78 After MOVE, contents of Amt-4 = 03 ^ 40

19 6-19 Numeric MOVE Rules If receiving field has fewer integer positions than sending field –High-order (leftmost) digits truncated If receiving field has fewer decimal positions than sending field –Low-order (rightmost) digits truncated

20 6-20 Numeric MOVE Example Operation: Move Amt-5 To Amt-6 Amt-5 Amt-6 Picture 99V99Picture 9V9 Contents 12 ^ 34Contents 5 ^ 6 Digits in integer part moved so that 2 replaces 5, 1 not moved Digits in decimal part moved so that 3 replaces 6, 4 not moved

21 6-21 Numeric MOVE Example Operation: Move Amt-5 To Amt-6 Amt-5 Amt-6 Picture 99V99Picture 9V9 Contents 12 ^ 34Contents 5 ^ 6 After MOVE, contents of Amt-6 = 2 ^ 3

22 6-22 Nonnumeric MOVE Sending field is alphanumeric field or nonnumeric literal Receiving field is alphanumeric field

23 6-23 Rules for Nonnumeric MOVE Characters moved from left to right If receiving field longer, low-order (rightmost) positions replaced with spaces If receiving field shorter, low-order characters in sending field truncated

24 6-24 Nonnumeric MOVE Example Operation: Move Code-1 To Code-2 Code-1 Code-2 Picture X(3) Picture X(6) Contents abc Contents mnopqr Characters abc replace mno Remaining three positions in Code-2 replaced with blanks

25 6-25 Nonnumeric MOVE Example Operation: Move Code-3 To Code-4 Code-3 Code-4 Picture X(5) Picture X(3) Contents vwxyz Contents efg Characters vwx replace efg y and z are not moved since all positions in Code-4 are filled

26 6-26 Group Moves When receiving field is group item, alphanumeric MOVE rules followed If subfields are numeric, invalid data may be stored in subfields

27 6-27 Group Move Example Operation: Move "ABCD" To WS-Code 01 WS-Code. 05 WS-Part-1 Pic XX. 05 WS-Part-2 Pic 99. After MOVE, value of WS-Part-1 is AB, WS-Part-2 is CD Causes error if WS-Part-2 then used in arithmetic operation

28 6-28 MOVE Operations Avoid using sending field with different data type than receiving field Move numeric fields, numeric literals or ZEROS to numeric fields Move alphanumeric fields, nonnumeric literals, ZEROS or SPACES to alphanumeric fields

29 6-29 Disk Files vs Output for Users Conciseness and efficiency important for data stored in disk files Clarity and readability important for output read by people –Displayed on screen –Printed in reports

30 6-30 Output for Users Edit symbols used to make data fields more readable –Display as $14.95 Use spacing between lines and page margins for readability Space fields across page or screen Heading and footing lines added to improve clarity of output

31 6-31 Editing Functions Report-item - elementary item that contains edit symbols in its PIC clause Editing occurs when elementary item moved to report-item PIC clause of report-item determines editing performed

32 6-32 Decimal Points Implied decimal points (V) do not print Move field with V in Picture to report- item field with actual decimal point for printing or displaying

33 6-33 Decimal Points Operation: Move In-Amt To Out-Amt Field Picture Contents Positions In-Amt 99V9912 ^ 344 Out-Amt Actual decimal point –Replaces implied one –Uses a storage position

34 6-34 Suppressing Leading Zeros Zeros in leftmost position of number usually suppressed –Value of number not affected and 25 have same value –Improves readability Edit symbol Z in PIC clause suppresses leading zeros, replaces with blanks

35 6-35 Suppressing Leading Zeros Use Z for each position where leading zero should be replaced by blank In-Qty Out-Qty Pic 999 Pic ZZZ 018b18 003bb bbb b denotes a blank (space) Examples 100 has no leading zeros so zeros not suppressed

36 6-36 Suppressing Leading Zeros To suppress only some leading zeros –Use Z's and 9's in same report-item Z's must precede 9's In-Qty Out-Qty Pic 999 Pic ZZ9 003bb3 000bb0 Examples

37 6-37 Zero Suppression and Decimals Zeros to right of decimal point are significant so they are not suppressed In-Cost Out-Cost Pic 99V99 Pic ZZ ^ 08 b ^ 02 bb ^ 00 bb.00 Examples

38 6-38 Dollar Signs and Commas $ and, often used in PICTURE clause with Z and decimal point Comma suppressed if only zeros precede it In-Cost Out-Cost Pic 9(4)V99 Pic $Z,ZZZ ^ 40$1, ^ 06$bbb ^ 04$bbbbb.04 Examples

39 6-39 Asterisks Check protection symbol Used in place of Z to replace leading zeros with * instead of space Prevents blanks from being filled in with numbers to change amount of check –$ could be changed to $3, –$***51.06 not easily changed

40 6-40 Asterisks WS-Chk-Amt Out-Chk-Amt Pic 9(4)V99 Pic $*,*** ^ 15 $2, ^ 08$*** ^ 06$*****.06 Examples

41 6-41 Plus or Minus Signs PIC clause with 9’s is unsigned field –Value assumed to be positive Use S with 9’s in PIC clause of sending field to define signed field –Use PIC of S9(3) to store -425 Report-item field must include + or - editing symbol to print or display a sign

42 6-42 Displaying Minus or Plus Sign Use - (minus) symbol to display minus sign if sending field is negative –Displays - for negative values –Displays blank (no sign) for positive or unsigned values Use + (plus) symbol to display sign for both positive and negative values –Displays - for negative values –Displays + for positive or unsigned values

43 6-43 Displaying Minus or Plus Sign Assume a PICTURE of S9(3) for WS-Amt Out-Amt WS-AmtPICTURE Contents ZZZ -bb ZZZ-218b ZZ9+b $ZZZ+$b30- Examples

44 6-44 Debit and Credit Symbols For accounting applications replace - (minus) sign with –DB to debit an account when negative –CR to credit an account when negative Always specified to right of report-item Print only when value moved to report item is negative

45 6-45 Debit and Credit Symbols Assume a PICTURE of S9(3) for WS-Amt Out-Amt WS-AmtPICTUREContents CR123CR DB123DB CR123bb DB123bb Examples

46 6-46 Spaces, Zeros, or Slashes B (space or blank), 0 (zero) or / (slash) may be inserted in report-item PIC as separator Used to edit either nonnumeric or numeric fields

47 6-47 Spaces, Zeros, or Slashes Assume PIC 9(3) for WS-Amt PIC X(3) for WS-Name Report-Item Contents PICTURE Contents WS-Amt BB9 52bb8 WS-Amt , ,000 WS-NameRAY XBXBX RbAbY WS-NameJAN X/X/X J/A/N Examples

48 6-48 Editing and Arithmetic Operations Editing performed when –Sending field moved to report-item –Result of arithmetic operations stored in report-item PICTURE of report-item determines type of editing

49 6-49 Editing and Arithmetic Operations All items used in arithmetic operation must be numeric Error if report-item used in calculation of result This statement invalid if Total-Out is report-item Add WS-Total To Total-Out Report-item may be used after GIVING

50 6-50 Editing with Floating Strings Used to place $, + or - directly preceding first significant digit For example, becomes $5.16 instead of $ 5.16 In edit string, replace all Z’s with floating character ($, + or -) Suppresses leading zeros, commas

51 6-51 Editing with Floating Strings Assume a PICTURE of S9(4)V99 for WS-Amt Out-Amt WS-AmtPICTURE Contents 0002 ^ 29 - $$,$$$.99bbbb$ ^ ,+++.99bbb ^ bb Examples

52 6-52 BLANK WHEN ZERO Option To print spaces when sending field is all zeros rather than $.00 or -0 For the report-item 05 Qty-Out Pic +++ Blank When Zero. 035 will print as will print as bbb (all spaces)

53 6-53 Defining Print Records Define each type of output line as separate 01-level record in WORKING- STORAGE May include 01-level records for heading, detail, total, footing lines, etc. Establishes separate storage area for each record All constants and blanks may be preassigned with VALUE clauses

54 6-54 WRITE … FROM Statement To transfer data from storage to print area and then print Replaces MOVE and WRITE Write Print-Rec From Heading-1 instead of Move Heading-1 to Print-Rec Write Print-Rec

55 6-55 ADVANCING Option Single spacing for WRITE is default Use AFTER or BEFORE ADVANCING to obtain any number of blank lines between each print line

56 6-56 WRITE Statement WRITE record-name-1 [FROM identifier-1] AFTER integer-1LINE BEFORE identifier-2LINES –integer-1 or identifier-2 must be non-negative integer value –AFTER ADVANCING prints line after paper is spaced –BEFORE ADVANCING prints line before spacing occurs FORMAT ADVANCING

57 6-57 WRITE … AFTER ADVANCING Write Print-Rec From Heading-Line-1 After Advancing 2 Lines –Causes paper to advance two lines –Heading-Line-1 printed on second line –Creates double spacing - one blank line followed by printed line

58 6-58 WRITE … BEFORE ADVANCING Write Print-Rec From Heading-Line-1 Before Advancing 2 Lines –Heading-Line-1 printed first, then spaces two lines –Results in overprinting if first line already contains printed output –As a rule, use either BEFORE or AFTER in program but not both

59 6-59 PAGE option Word PAGE after ADVANCING causes paper to advance to next page To advance paper to top of new page and print a heading, code Write Print-Rec From Heading-Line-1 After Advancing Page

60 6-60 End-of-Page Control When page is full, need to advance to next page and print headings again Define WORKING-STORAGE field for line counter Initialize line counter to zero and increment it each time a line is printed When line counter equals or exceeds line limit for page, advance to next page

61 6-61 Printing Page Numbers Define WORKING-STORAGE field for page number Initialize and then increment page number each time new page begins Move page number to report-item in heading line before printing it at top of a new page

62 6-62 Accessing Date of Run To get current date in program, access reserved word DATE Stores date as six-digit field, two digits each for year, month and day January 25, 2003 stored as

63 6-63 Accessing Date of Run ACCEPT identifier-1 FROM DATE For older compilers identifier must be defined as numeric field to hold 6 digits FORMAT

64 6-64 Accessing Date of Run Accept WS-Date From Date Where WS-Date defined as: 01WS-Date. 05Run-YearPic Run-MonthPic Run-DayPic 99. EXAMPLE

65 6-65 Printing Date of Run WS-Date fields typically reformatted for printing Moved to report-item fields listed in month, day, year order with slashes between them

66 6-66 Date with Four-Digit Year Newer compilers provide access to full four- digit year Use intrinsic function CURRENT-DATE with MOVE in place of ACCEPT –Change Run-Year in WS-Date to Pic 9(4) Move Function Current-Date To WS-Date –If date is January 25, 2003 then 2003 will be stored in Run-Year

67 6-67 Report Design Guidelines 1.Include heading to identify report 2.Include date, page number 3.Include column headings to identify fields printed 4.Place most significant fields where they are most visible 5.Edit numeric fields for readability

68 6-68 Report Design Guidelines 6.Include totals at end of page or report 7.Use *’s to identify level of total Dept Total is $33,266.25* Final total is $167,267.53** 8.Include page footings at end of each page, report footings at end of report EXAMPLE

69 6-69 Displaying Output Interactively No COBOL standard for interactive processing Two techniques used by compilers to add interactivity –ACCEPT, DISPLAY enhancements with options to define appearance of data on screen –SCREEN SECTION added in DATA DIVISON to define screen’s format

70 6-70 ACCEPT, DISPLAY Enhancements Display "Enter date of birth" At Line 13 Column 1 With Blank Screen Foreground-Color 1 Background-Color 7 Displays prompt at specific position on screen after clearing screen, using one color for characters and another for background EXAMPLE

71 6-71 SCREEN SECTION Specify formats, options for screen Follows WORKING-STORAGE Define each screen with 01 level entry followed by subordinate entries DISPLAY screen-name displays all prompts described in entries for screen ACCEPT screen-name captures all data typed by user for that screen

72 6-72 SCREEN SECTION 01Screen-1. 05Blank Screen. 05Line 3 Column 1 Value 'City'. 05Column 17 Pic X(13) To City-In. Display Screen-1 blanks screen and displays City in first column of line 3 Accept Screen-1 moves 13 characters user enters starting in line 3, column 17 to City-In EXAMPLE

73 6-73 COBOL 2008 Changes Will be able to use report-items in arithmetic operations Will be able to combine or concatenate nonnumeric literals in MOVE statement Move'Stu-Name Credits' & ' Tuition Scholarship' To Column-Heading-Line

74 6-74 Chapter Summary Numeric MOVE Rules Decimal alignment maintained Integer and decimal portion digits moved from decimal point out Nonfilled high-, low-order positions replaced with zeros Truncation of high-, low-order digits occurs if receiving field not large enough

75 6-75 Chapter Summary Nonnumeric MOVE Rules Movement from left to right Low-order nonfilled positions replaced with spaces Low-order characters truncated if receiving field not large enough

76 6-76 Chapter Summary Format of receiving field determines type of MOVE operation See Table 6.3 in text for summary of edit symbols

77 6-77 Chapter Summary Rules for Printing Output –Use Printer Spacing Chart to determine print positions to be used –Define all printed output in WORKING- STORAGE so VALUE clause can be used –Use appropriate editing symbols in report- items

78 6-78 Chapter Summary WRITE statement clauses –Move records to print area in FILE SECTION with WRITE … FROM –Use BEFORE or AFTER ADVANCING to control spacing between lines –Use AFTER ADVANCING PAGE to go to beginning of next page

79 6-79 Chapter Summary Interactive Input/Output –Use SCREEN SECTION or enhanced ACCEPT, DISPLAY verbs to make screen displays more user friendly –Options available to Describe exact line, column for item Add color, sounds Highlight, blink, underline, reverse video item Clear all or part of screen

80 6-80 Copyright © 2003 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in Section 117 of the 1976 United States Copyright Act without the express written permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages, caused by the use of these programs or from the use of the information contained herein.

81 6-81 Moving Data, Printing Information, and Displaying Output Interactively Chapter 6


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