1 / 15

Understanding Procedure Division in COBOL Programming

Learn about PERFORM, inline PERFORM, conditional branches, STRING, UNSTRING, INSPECT statements in COBOL's Procedure Division. Figure illustrations provide a clear guide on COBOL program structures and processing techniques. Enhance your COBOL programming skills with detailed explanations and examples.

vvick
Download Presentation

Understanding Procedure Division in COBOL Programming

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 9 – More on Procedure Division • PERFORM • TEST BEFORE/TEST AFTER • Inline Perform • not calling a procedure • Performing Sections • can be a paragraph or a section • paragraph - one or more sentances • section - one or more paragraphs

  2. Figure 9.1 The Iteration Structure A CONDITION? TRUE A CONDITION? FALSE FALSE TRUE (a) DO WHILE Construct (b) DO UNTIL Construct

  3. READ INPUT-FILE AT END MOVE ‘NO’ TO DATA-REMAINS-SWITCH.PERFORM PROCESS-RECORDS UNTIL DATA-REMAINS-SWITCH = ‘NO’. PROCESS-RECORDS.. . . READ INPUT-FILE AT END MOVE ‘NO’ TO DATA-REMAINS-SWITCH. (a) Priming Read PERFORM UNTIL DATA-REMAINS-SWITCH = ‘NO’ READ INPUT-FILE AT END MOVE ‘NO’ TO DATA-REMAINS-SWITCH NOT AT END . . . END-READEND-PERFORM. (b) False Condition Branch with In-Line Perform Figure 9.2 Structure of a COBOL Program Procedure Division statements to process the current record Procedure Division statements to process the current record

  4. PERFORM THRU • executes statements between procedure names. • PERFORM PROCESS1 THRU PROCESS4 • READ • False Condition Branch • NOT AT END • way to avoid the priming read • READ INTO • read data into 2 places, working storage and the I/O area.

  5. WRITE FORM • same as READ INTO but used for writing a record. WRITE HEADING-LINE FROM WS-PRINT-LINE = MOVE WS-PRINT-LINE TO HEADING-LINE WRITE HEADING-LINE • String Processing • INSPECT - find/replace • STRING - joins strings • UNSTRING - splits strings

  6. Figure 9.3 The READ INTO statement FD EMPLOYEE-FILE DATA RECORD IS EMPLOYEE-RECORD.01 EMPLOYEE-RECORD PIC X(60). . . .WORKING-STORAGE SECTION.01 FILLER PIC X(14) VALUE ‘WS BEGINS HERE’.01 WS-EMPLOYEE-RECORD. 05 EMP-NAME PIC X(25). . . . PROCEDURE DIVISION. . . . READ EMPLOYEE-FILE INTO WS-EMPLOYEE-RECORD AT END MOVE ‘NO’ TO DATA-REMAINS-SWITCH NOT AT END PERFORM PROCESS-THIS-RECORD END-READ.

  7. Figure 9.4 The INSPECT statement 01 RECORD-IN. 05 SOC-SEC-NUM PIC 9(9). . . .01 PRINT-LINE. 05 SOC-SEC-NUM-OUT PIC 999B99B9999. . . . PROCEDURE DIVISION. . . . MOVE SOC-SEC-NUM TO SOC-NUM-OUT. INSPECT SOC-SEC-NUM-OUT REPLACING ALL ‘ ‘ BY ‘-’. Initial: SOC-SEC-NUM 123 45 6789 Result: SOC-SEC-NUM-OUT 123-45-6789

  8. Before Execution LAST-NAME S M I T H MIDDLE-INITIAL H FIRST-NAME J O H N ENTIRE-NAME Figure 9.5 The STRING Statement 05 NAME-IN-PIECES. 10 LAST-NAME PIC X(16). 10 FIRST-NAME PIC X(10). 10 MIDDLE-INITIAL PIC X. 05 ENTIRE-NAME PIC X(29). (a) Working-Storage Holding Areas

  9. (1) ENTIRE-NAME J O H N (2) ENTIRE-NAME J O H N (b) (3) ENTIRE-NAME J O H N (b) H (4) ENTIRE-NAME J O H N (b) H (b) (5) ENTIRE-NAME J O H N (b) H (b) S M I T H Figure 9.5 The STRING Statement (cont.) MOVE SPACES TO ENTIRE-NAME.STRING FIRST-NAME DELIMITED BY SPACE ‘ ‘ DELIMITED BY SIZE MIDDLE-INITIAL DELIMITED BY SPACE ‘ ‘ DELIMITED BY SIZE LAST-NAME DELIMITED BY SPACE INTO ENTIRE-NAME (b) STRING Statement Execution Steps (c) Sequence of transfer

  10. Before Execution LAST-NAME MIDDLE-INITIAL FIRST-NAME ENTIRE-NAME J O H N (b) H (b) S M I T H Figure 9.6 The UNSTRING Statement 05 NAME-IN-PIECES. 10 LAST-NAME PIC X(16). 10 FIRST-NAME PIC X(10). 10 MIDDLE-INITIAL PIC X. 05 ENTIRE-NAME PIC X(31). (a) Working-Storage Holding Areas MOVE SPACES TO NAME-IN-PIECES.UNSTRING ENTIRE-NAME DELIMITED BY ‘ ‘ INTO FIRST-NAME MIDDLE-INITIAL LAST-NAME. (b) UNSTRING Statement

  11. J O H N S M I T H (1) ENTIRE-NAME J O H N (b) H (b) S M I T H Figure 9.6 The UNSTRING Statement (1) ENTIRE-NAME J O H N (b) H (b) S M I T H H FIRST-NAME MIDDLE-INITIAL LAST-NAME (c) Execution of UNSTRING

  12. FD PRINT-FILE DATA RECORD IS PRINT-LINE.01 PRINT-LINE PIC X(80). PROCEDURE DIVISION. . . MOVE HEADING-LINE TO PRINT-LINE. WRITE PRINT-LINE AFTER ADVANCING PAGE. (a) Two instruction process FD PRINT-FILE DATA RECORD IS PRINT-LINE.01 PRINT-LINE PIC X(80).. .01 HEADING-LINE. 03 PIC X(17) VALUE SPACES. 03 PIC X(25) VALUE ‘ INVENTORY REPORT PREPARED BY GARPL’. PROCEDURE DIVISION.. . WRITE PRINT-LINE FROM HEADING-LINE AFTER ADVANCING PAGE. (b) One instruction process The WRITE FROM statement

  13. INITALIZE • 01 GROUP-ITEM • 05 NUMERIC-FIELD PIC 9(4) • 05 ALPHANUMERIC-FIELD PIC X(15) INITIALIZE GROUP-ITEM == MOVE ZEROS TO NUMERIC-FIELD MOVE SPAES TO ALPHANUMERIC-FIELD INITIALIZE GROUP-ITEM REPLACING NUMERIC BY ZERO == MOVE ZEROS TO NUMERIC-FIELD

  14. The INITIALIZE statement • Sets elementary or group data names to ‘initial’ value • DOES NOT RESET VALUE TO THAT OF THE VALUE STATEMENT!!! • EX: 01 GROUP-ITEM. 05 NUMERIC-FIELD-1 PIC 9(4). 05 NUMERIC-FIELD-2 PIC 9(4). 05 ALPHANUMERIC-FIELD-1 PIC X(15). 05 ALPHANUMERIC-FIELD-2 PIC X(20). • The statement INITIALIZE GROUP-ITEM • is equivalent to the combined statements: MOVE ZEROS TO NUMERIC-FIELD-1. MOVE ZEROS TO NUMERIC-FIELD-2. MOVE SPACES TO ALPHANUMERIC-FIELD-1. MOVE SPACES TO ALPHANUMERIC-FIELD-2.

  15. ACCEPT • Duplicate Data Names • Qualification • MOVE CORRESPONDING • The Car billing program • Program design • The Completed Program

More Related