Nested IF-ELSE vs. EVALUATE

       IDENTIFICATION DIVISION. 
       PROGRAM-ID.     ANOTHER-EXAMPLE.
       AUTHOR.         BILL ROGERS.

      *  This program illustrates the Nested IF structure 
      *  compared to the EVALUATE verb.  The Nested IF and
      *  EVALUATE shown here are logically the same.

       ENVIRONMENT DIVISION. 

       DATA DIVISION. 

       WORKING-STORAGE SECTION. 

       01 KBD-ENTRY PIC X.

       PROCEDURE DIVISION. 

       MAIN-LINE. 
           PERFORM DO-SETUP.
           PERFORM DO-NESTED-IF.
           PERFORM DO-EVALUATE.
           STOP RUN.

       DO-SETUP.
           DISPLAY 'Enter a digit '.
           ACCEPT KBD-ENTRY.

       DO-NESTED-IF.
           IF KBD-ENTRY = '1'
              DISPLAY 'Freshman'
           ELSE IF KBD-ENTRY = '2'
                   DISPLAY 'Sophomore'
                ELSE IF KBD-ENTRY = '3'
                        DISPLAY 'Junior'
                     ELSE IF KBD-ENTRY = '4'
                             DISPLAY 'Senior'
                          ELSE IF KBD-ENTRY = '5'
                                  DISPLAY 'Graduate'
                               ELSE
                                  DISPLAY 'Undefined code'
                               END-IF
                          END-IF
                     END-IF
                END-IF
           END-IF.

       DO-EVALUATE.
           EVALUATE KBD-ENTRY
               WHEN '1'    DISPLAY 'Freshman'
               WHEN '2'    DISPLAY 'Sophomore'
               WHEN '3'    DISPLAY 'Junior'
               WHEN '4'    DISPLAY 'Senior'
               WHEN '5'    DISPLAY 'Graduate'
               WHEN OTHER  DISPLAY 'Undefined code'
           END-EVALUATE.

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