Let's understand Mainframe
Home Tutorials Interview Q&A Quiz Mainframe Memes Contact us About us

MODULE 7: COBOL Control statements


PERFORM for Multi-dimensional arrays

  • Also referred to as "PERFORM with VARYING AFTER"
  • This kind of PERFORM browse through each elements of multi-dimensional array. For this purpose, we can use PERFORM in below specified format (below is simplified syntax for 2-dimentional array look up)
  • Basic syntax:-

    PERFORM [para-1 [{THRU/THROUGH} para-n]]       VARYING id-1 FROM id-2       BY id-3 UNTIL condition-1       AFTER VARYING id-4 FROM id-5       BY id-6 UNTIL condition-2       [statement-block  END-PERFORM]

    Where,
    • para-1, para-n are paragraph names which we want to call
    • id-1,id-4 can be numeric data item or index data item
    • id-2,id-5 can be numeric data item or index data item or literal
    • id-3,id-6 can be numeric data item or literal
    • condition-1, condition-2 is any conditional-expression which can either return true or false
    • [statement-block END-PERFORM] is used for Inline PERFORM.
  • Example:-
    Suppose, we have data stored in our array (table) in below format
    In DATA DIVISION,

    01 DEPARTMENT-TABLE. 05 DEPARTMENT OCCCURS 3 TIMES. 10 DEPT-NAME PIC X(20). 10 EMP-NAME PIC X(20) OCCURS 2 TIMES.

    Visually it will have data like:-
    Reference visual:-
    DEPT-NAME(1) EMP-NAME(1,1) EMP-NAME(1,2)
    DEPT-NAME(2) EMP-NAME(2,1) EMP-NAME(2,2)
    DEPT-NAME(3) EMP-NAME(3,1) EMP-NAME(3,2)
    Values visual:-
    MANUFACTURING RAMESH AKSHAY
    QUALITY STEVE JOY
    MARKETING ASHWANI JEFF
    In PROCUEDURE DIVISION, we can write below code to display each elements of above multi-dimensional table

    PARA-0. PERFORM PARA-1 THRU PARA-1-EXIT VARYING DEPT-I FROM 1 BY 1 UNTIL DEPT-I > 3 AFTER VARYING DEPT-J 1 BY 1 UNTIL DEPT-J > 2. STOP RUN. PARA-1. DISPLAY ‘DEPARTMENT: ’ DEPT-NAME(DEPT-I) DISPLAY ‘EMP-NAME: ’ EMP-NAME(DEPT-I, DEPT-J) PARA-1-EXIT. EXIT.

    SYSOUT display (output):-

    DEPARTMENT: MANUFACURING EMP-NAME: RAMESH DEPARTMENT: MANUFACURING EMP-NAME: AKSHAY DEPARTMENT: QUALITY EMP-NAME: STEVE DEPARTMENT: QUALITY EMP-NAME: JOY DEPARTMENT: MARKETING EMP-NAME: ASHWANI DEPARTMENT: MARKETING EMP-NAME: JEFF

  • You will be able to understand how the program has processed in above example by mapping reference visuals, values visuals and SYSOUT displays.



Advertisements






© copyright mainframebug.com
Privacy Policy