The FOR ... ENDFOR Construct

The FOR ... ENDFOR functionality is achieved by the following syntax :

PERFORM paragraph-name VARYING variable-1 FROM start-value 
                              BY incr-value UNTIL condition.

PERFORM parag-first THRU parag-last VARYING variable-1 FROM start-value 
                              BY incr-value UNTIL condition.

Note : For a definition of the PARAGRAPH concept, you can have a look at DO UNTIL page.

The following statement will perform the indicated paragraph 10 times, but at each loop cycle, the value of variable K will be incremented by one:

      PERFORM VALIDITY-TEST VARYING K FROM 1 BY 1 UNTIL K > 10.
      ...
      ...
  VALIDITY-TEST.
      IF ARRAY-OF-VALUES (K) > 0
         ADD 1 TO VALID-ITEM-COUNT
         ADD ARRAY-OF-VALUES(K) TO SOME-VARIABLE
         DISPLAY "A VALID ENTRY FOUND".
  QUALITY-TEST.
      ....
      ....

An example as the following perfectly makes sense if you need to execute validity, color, weight and quality tests for the first 10 elements of the array.

      PERFORM VALIDITY-TEST THRU QUALITY-TEST VARYING K 
                            FROM 1 BY 1 UNTIL K > 10.
      ...
      ...
  VALIDITY-TEST.
      IF ARRAY-OF-VALUES (K) > 0
         ADD 1 TO VALID-ITEM-COUNT
         ADD ARRAY-OF-VALUES(K) TO SOME-VARIABLE
         DISPLAY "A VALID ENTRY FOUND".
  COLOR-TEST.
      ....
      ....
  WEIGHT-TEST.
      ....
      ....
  QUALITY-TEST.
      ....
      ....

This is simply the FOR .. ENDFOR contruct that you will need to produce structured code.

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