Conditionals: IF & EVALUATE

14.1 IF / ELSE / END-IF

Always close with END-IF. A stray period inside an IF ends the whole statement — the classic COBOL bug:

IF WS-BALANCE < 0
               DISPLAY "Overdrawn"
               ADD 1 TO WS-OVERDRAWN-COUNT
           ELSE
               IF WS-BALANCE > 10000
                   DISPLAY "Premium customer"
               ELSE
                   DISPLAY "Regular customer"
               END-IF
           END-IF

* BUG: the period after the first DISPLAY ends the IF,
      * so "ADD 1" executes for every record!
           IF WS-AMOUNT > 1000
               DISPLAY "Large amount".
               ADD 1 TO WS-LARGE-COUNT

14.2 Kinds of conditions

IF A > B, IF A IS GREATER THAN OR EQUAL TO B, IF A NOT = B

IF WS-INPUT IS NUMERIC, ALPHABETIC, ALPHABETIC-UPPER, ALPHABETIC-LOWER

IF WS-AMT IS POSITIVE, NEGATIVE, ZERO Condition name (88) IF END-OF-FILE, IF NOT VALID-STATUS IF A > 0 AND (B = 1 OR C = 2)

IF WS-CODE = "A" OR "B" OR "C" (subject and operator implied)

The NUMERIC class test is essential for validating input before arithmetic — non-numeric data in a numeric field causes the infamous S0C7 data exception abend on z/OS.

14.3 EVALUATE — COBOL's powerful case statement

WHEN clauses are tested in order; the first match wins (no fall-through).

Consecutive WHENs with no statements share the next statement group (like WHEN 6 above).

ANY matches anything; NOT negates a value (WHEN NOT "X").

* Evaluate a single subject
           EVALUATE WS-DAY-NUM
               WHEN 1 THRU 5   DISPLAY "Weekday"
               WHEN 6
               WHEN 7          DISPLAY "Weekend"
               WHEN OTHER      DISPLAY "Invalid day"
           END-EVALUATE

      * EVALUATE TRUE: a clean replacement for nested IFs
           EVALUATE TRUE
               WHEN WS-SCORE >= 90  MOVE "A" TO WS-GRADE
               WHEN WS-SCORE >= 80  MOVE "B" TO WS-GRADE
               WHEN WS-SCORE >= 70  MOVE "C" TO WS-GRADE
               WHEN WS-SCORE >= 60  MOVE "D" TO WS-GRADE
               WHEN OTHER           MOVE "F" TO WS-GRADE
           END-EVALUATE

      * Multiple subjects with ALSO: a decision table
           EVALUATE WS-CUST-TYPE ALSO TRUE
               WHEN "G"          ALSO WS-ORDER-AMT > 1000
                   MOVE 0.15 TO WS-DISCOUNT
               WHEN "G"          ALSO ANY
                   MOVE 0.10 TO WS-DISCOUNT
               WHEN "R"          ALSO WS-ORDER-AMT > 1000
                   MOVE 0.05 TO WS-DISCOUNT
               WHEN OTHER
                   MOVE 0    TO WS-DISCOUNT
           END-EVALUATE

14.4 CONTINUE and NEXT SENTENCE

CONTINUE is a no-operation placeholder (IF A = B CONTINUE ELSE ...). NEXT SENTENCE jumps past the next period — dangerous with scope terminators; avoid it in new code.