* ==== TYPE: MT01 MATCHING(1:1) ====
      * FEATURE: 2 input files, IF KEY = compare, 3-way IF
      * BRANCHES: 4, DECISIONS: 2
       IDENTIFICATION DIVISION.
       PROGRAM-ID. MT01.
       ENVIRONMENT DIVISION.
       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
           SELECT FILE-A ASSIGN TO 'FILEA.DAT'.
           SELECT FILE-B ASSIGN TO 'FILEB.DAT'.
       DATA DIVISION.
       FILE SECTION.
       FD FILE-A.
       01 REC-A PIC X(80).
       FD FILE-B.
       01 REC-B PIC X(80).
       WORKING-STORAGE SECTION.
       01 WS-KEY-A PIC X(10).
       01 WS-KEY-B PIC X(10).
       01 WS-EOF-A PIC X VALUE 'N'.
       01 WS-EOF-B PIC X VALUE 'N'.
       PROCEDURE DIVISION.
       MAIN-PROCEDURE.
           OPEN INPUT FILE-A FILE-B.
           READ FILE-A INTO REC-A
               AT END MOVE 'Y' TO WS-EOF-A.
           READ FILE-B INTO REC-B
               AT END MOVE 'Y' TO WS-EOF-B.
           PERFORM UNTIL WS-EOF-A = 'Y' OR WS-EOF-B = 'Y'
               IF WS-KEY-A = WS-KEY-B
                   DISPLAY 'MATCH: ' REC-A(1:50)
                   READ FILE-A AT END MOVE 'Y' TO WS-EOF-A
                   READ FILE-B AT END MOVE 'Y' TO WS-EOF-B
               ELSE IF WS-KEY-A < WS-KEY-B
                   DISPLAY 'UNMATCH-A: ' REC-A(1:50)
                   READ FILE-A AT END MOVE 'Y' TO WS-EOF-A
               ELSE
                   DISPLAY 'UNMATCH-B: ' REC-B(1:50)
                   READ FILE-B AT END MOVE 'Y' TO WS-EOF-B
               END-IF
           END-PERFORM.
           CLOSE FILE-A FILE-B.
           STOP RUN.