COBOL Array Index Example

Table Processing Tutorial   

Scenario - Declaring an index, initialized, incremented and used to navigate the table.

Code -

----+----1----+----2----+----3----+----4----+----5----+
       IDENTIFICATION DIVISION.
       PROGRAM-ID. TBINDEX.

       DATA DIVISION. 
       WORKING-STORAGE SECTION.
	  * Declaring table with index
       01 WS-CLASS.
          03 WS-STUDENT  OCCURS 2 TIMES INDEXED BY WS-IDX.
             05 WS-ROLL-NO      PIC X(03).
             05 WS-NAME         PIC X(10).

       PROCEDURE DIVISION.
      * Initializing index to 1 
		   SET WS-IDX          TO 1.
		   MOVE "001PAWAN Y"   TO WS-STUDENT(WS-IDX).

      * Incrementing index by 1
		   SET WS-IDX          UP BY 1.
		   MOVE "002KUMAR"     TO WS-STUDENT(WS-IDX).

      * Displaying full table using index
           PERFORM VARYING WS-IDX FROM 1 BY 1 UNTIL WS-IDX > 2  
                   DISPLAY "STUDENT - " WS-STUDENT(WS-IDX)
           END-PERFORM.
           STOP RUN.

Output -

STUDENT - 001PAWAN Y 
STUDENT - 002KUMAR

Explaining Example -

In the above example:

  • It defines a table WS-CLASS with an index WS-IDX, consisting of student records with roll numbers and names.
  • It then initializes the index to 1 and assigns values to the table entries using the index.
  • After incrementing the index, it displays the entire table by iterating over the index using a PERFORM loop, displaying each student's information.