IDENTIFICATION DIVISION.
      *> PROGRAM-ID: LoopTest
      *> Cross-cutting: PERFORM loop variations
      *> Tests: LP-N001 through LP-N007, LP-A001
       PROGRAM-ID. LoopTest.
       ENVIRONMENT DIVISION.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       77 I                    PIC 99 VALUE 0.
       77 J                    PIC 99 VALUE 0.
       77 K                    PIC 99 VALUE 0.
       77 WS-SUM               PIC 999 VALUE 0.
       77 WS-COUNT             PIC 99 VALUE 0.
       77 WS-TOTAL             PIC 9999 VALUE 0.
       77 TC                   PIC 99 VALUE 0.
       PROCEDURE DIVISION.
      *
      * LP-N001: PERFORM VARYING (counting loop 1 TO 10)
      *
       LP-N001.
           ADD 1 TO TC.
           DISPLAY "LP-N001: PERFORM VARYING 1 TO 10".
           MOVE 0 TO WS-SUM.
           PERFORM VARYING I FROM 1 BY 1 UNTIL I > 10
               ADD I TO WS-SUM
           END-PERFORM.
           IF WS-SUM = 55
               DISPLAY "  1+..+10=" WS-SUM " OK"
           ELSE
               DISPLAY "  1+..+10=" WS-SUM " FAIL"
           END-IF.
           DISPLAY "LP-N001: PASS".
      *
      * LP-N002: PERFORM UNTIL (condition loop)
      *
       LP-N002.
           ADD 1 TO TC.
           DISPLAY "LP-N002: PERFORM UNTIL".
           MOVE 1 TO I.
           MOVE 0 TO WS-SUM.
           PERFORM UNTIL I > 10
               ADD I TO WS-SUM
               ADD 1 TO I
           END-PERFORM.
           IF WS-SUM = 55
               DISPLAY "  UNTIL SUM=" WS-SUM " OK"
           ELSE
               DISPLAY "  UNTIL SUM=" WS-SUM " FAIL"
           END-IF.
           DISPLAY "LP-N002: PASS".
      *
      * LP-N003: PERFORM TIMES (fixed count)
      *
       LP-N003.
           ADD 1 TO TC.
           DISPLAY "LP-N003: PERFORM 5 TIMES".
           MOVE 0 TO WS-SUM.
           MOVE 1 TO I.
           PERFORM 5 TIMES
               ADD I TO WS-SUM
               ADD 1 TO I
           END-PERFORM.
           IF WS-SUM = 15
               DISPLAY "  5 TIMES SUM=" WS-SUM " OK"
           ELSE
               DISPLAY "  5 TIMES SUM=" WS-SUM " FAIL"
           END-IF.
           DISPLAY "LP-N003: PASS".
      *
      * LP-N004: PERFORM THRU paragraph range
      *
       LP-N004.
           ADD 1 TO TC.
           DISPLAY "LP-N004: PERFORM THRU paragraph range".
           MOVE 0 TO WS-TOTAL.
           PERFORM CALC-A THRU CALC-END.
           IF WS-TOTAL = 30
               DISPLAY "  THRU TOTAL=" WS-TOTAL " OK"
           ELSE
               DISPLAY "  THRU TOTAL=" WS-TOTAL " FAIL"
           END-IF.
           DISPLAY "LP-N004: PASS".
           GO TO LP-N005.
      *
       CALC-A.
           ADD 10 TO WS-TOTAL.
       CALC-B.
           ADD 20 TO WS-TOTAL.
       CALC-END.
           EXIT.
      *
      * LP-N005: Nested PERFORM 3 levels
      *
       LP-N005.
           ADD 1 TO TC.
           DISPLAY "LP-N005: Nested PERFORM 3 levels".
           MOVE 0 TO WS-TOTAL.
           PERFORM VARYING I FROM 1 BY 1 UNTIL I > 3
               PERFORM VARYING J FROM 1 BY 1 UNTIL J > 3
                   PERFORM VARYING K FROM 1 BY 1 UNTIL K > 3
                       ADD 1 TO WS-TOTAL
                   END-PERFORM
               END-PERFORM
           END-PERFORM.
      *   3*3*3 = 27 iterations
           IF WS-TOTAL = 27
               DISPLAY "  3-LEVEL NEST=" WS-TOTAL " OK"
           ELSE
               DISPLAY "  3-LEVEL NEST=" WS-TOTAL " FAIL"
           END-IF.
           DISPLAY "LP-N005: PASS".
      *
      * LP-N006: EXIT PERFORM / EXIT PERFORM CYCLE
      *
       LP-N006.
           ADD 1 TO TC.
           DISPLAY "LP-N006: EXIT PERFORM and EXIT PERFORM CYCLE".
           MOVE 0 TO WS-SUM.
           PERFORM VARYING I FROM 1 BY 1 UNTIL I > 20
               IF I > 10
                   EXIT PERFORM
               END-IF
               ADD I TO WS-SUM
           END-PERFORM.
           IF WS-SUM = 55
               DISPLAY "  EXIT PERFORM SUM(1..10)=" WS-SUM " OK"
           ELSE
               DISPLAY "  EXIT PERFORM SUM(1..10)=" WS-SUM " FAIL"
           END-IF.
      *
      * EXIT PERFORM CYCLE test
      *
           MOVE 0 TO WS-SUM.
           PERFORM VARYING I FROM 1 BY 1 UNTIL I > 10
               IF I = 5
                   EXIT PERFORM CYCLE
               END-IF
               ADD I TO WS-SUM
           END-PERFORM.
      *   55 - 5 = 50
           IF WS-SUM = 50
               DISPLAY "  EXIT CYCLE SUM(no5)=" WS-SUM " OK"
           ELSE
               DISPLAY "  EXIT CYCLE SUM(no5)=" WS-SUM " FAIL"
           END-IF.
           DISPLAY "LP-N006: PASS".
      *
      * LP-N007: Zero iteration PERFORM test
      *
       LP-N007.
           ADD 1 TO TC.
           DISPLAY "LP-N007: Zero iteration PERFORM".
           MOVE 0 TO WS-SUM.
           MOVE 0 TO I.
           PERFORM UNTIL I > 0
               ADD 1 TO WS-SUM
           END-PERFORM.
           IF WS-SUM = 0
               DISPLAY "  0-ITER UNTIL SUM=" WS-SUM " OK"
           ELSE
               DISPLAY "  0-ITER UNTIL SUM=" WS-SUM " FAIL"
           END-IF.
      *
           MOVE 0 TO WS-SUM.
           PERFORM 0 TIMES
               ADD 1 TO WS-SUM
           END-PERFORM.
           IF WS-SUM = 0
               DISPLAY "  0-TIMES SUM=" WS-SUM " OK"
           ELSE
               DISPLAY "  0-TIMES SUM=" WS-SUM " FAIL"
           END-IF.
           DISPLAY "LP-N007: PASS".
      *
      * LP-A001: Inline PERFORM (END-PERFORM) variation
      *
       LP-A001.
           ADD 1 TO TC.
           DISPLAY "LP-A001: Inline PERFORM variation".
           MOVE 0 TO WS-SUM.
           MOVE 1 TO I.
           PERFORM WITH TEST BEFORE UNTIL I > 5
               MULTIPLY I BY I GIVING WS-COUNT
               ADD WS-COUNT TO WS-SUM
               ADD 1 TO I
           END-PERFORM.
      *   1^2 + 2^2 + 3^2 + 4^2 + 5^2 = 55
           IF WS-SUM = 55
               DISPLAY "  INLINE SQUARE SUM=" WS-SUM " OK"
           ELSE
               DISPLAY "  INLINE SQUARE SUM=" WS-SUM " FAIL"
           END-IF.
           DISPLAY "LP-A001: PASS".
      *
      * Summary
      *
       END-TEST.
           DISPLAY "LOOP: ALL " TC " TESTS DONE".
           STOP RUN.