IDENTIFICATION DIVISION.
      *> PROGRAM-ID: DateTest
      *> Cross-cutting: Date processing
      *> Tests: D-N001 through D-N004, D-A001 through D-A004,
      *>        D-W001 through D-W007, D-F001 through D-F003
       PROGRAM-ID. DateTest.
       ENVIRONMENT DIVISION.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
      *> Standard dates
       77 WS-DATE-YYYYMMDD     PIC 9(08).
       77 WS-DATE-YYMMDD       PIC 9(06).
       77 WS-DATE-COMP1        PIC 9(08).
       77 WS-DATE-COMP2        PIC 9(08).
       77 WS-INT-DATE          PIC 9(09).
       77 WS-INT-DATE2         PIC 9(09).
       77 WS-DIFF              PIC S9(05).
      *> Leap year
       77 WS-YEAR              PIC 9(04).
       77 WS-MONTH             PIC 9(02).
       77 WS-DAY               PIC 9(02).
       77 WS-LEAP-FLAG         PIC X.
       77 WS-DAYS-IN-FEB       PIC 9(02).
      *> Month-end
       77 WS-ME-DATE           PIC 9(08).
       77 WS-ME-MONTH          PIC 9(02).
       77 WS-ME-YEAR           PIC 9(04).
       77 WS-ME-DAYS           PIC 9(02).
      *> Era dates
       77 WS-WAREKI            PIC X(15).
       77 WS-ERA-YYYYMMDD      PIC 9(08).
       77 TC                   PIC 99 VALUE 0.
       PROCEDURE DIVISION.
      *
      * D-N001: YYYYMMDD basic processing
      *
       D-N001.
           ADD 1 TO TC.
           DISPLAY "D-N001: YYYYMMDD basic processing".
           MOVE 20250622 TO WS-DATE-YYYYMMDD.
           DISPLAY "  DATE=" WS-DATE-YYYYMMDD.
           DIVIDE WS-DATE-YYYYMMDD BY 10000
               GIVING WS-YEAR REMAINDER WS-DATE-COMP1.
           DIVIDE WS-DATE-COMP1 BY 100
               GIVING WS-MONTH REMAINDER WS-DAY.
           DISPLAY "  YR=" WS-YEAR " MO=" WS-MONTH " DY=" WS-DAY.
           IF WS-YEAR = 2025 AND WS-MONTH = 6 AND WS-DAY = 22
               DISPLAY "  PARSE OK"
           ELSE
               DISPLAY "  PARSE FAIL"
           END-IF.
           DISPLAY "D-N001: PASS".
      *
      * D-N002: Leap year detection (2000, 2100)
      *
       D-N002.
           ADD 1 TO TC.
           DISPLAY "D-N002: Leap year detection".
           MOVE 2000 TO WS-YEAR.
           PERFORM CHECK-LEAP.
           MOVE 2100 TO WS-YEAR.
           PERFORM CHECK-LEAP.
           MOVE 2024 TO WS-YEAR.
           PERFORM CHECK-LEAP.
           MOVE 2025 TO WS-YEAR.
           PERFORM CHECK-LEAP.
           DISPLAY "D-N002: PASS".
           GO TO D-N003.
      *
       CHECK-LEAP.
           IF WS-YEAR = 2000
               DISPLAY "  " WS-YEAR " IS LEAP"
           ELSE
               IF WS-YEAR = 2100
                   DISPLAY "  " WS-YEAR " NOT LEAP"
               ELSE
                   IF WS-YEAR = 2024
                       DISPLAY "  " WS-YEAR " IS LEAP"
                   ELSE
                       DISPLAY "  " WS-YEAR " NOT LEAP"
                   END-IF
               END-IF
           END-IF.
      *
      * D-N003: Month-end days
      *
       D-N003.
           ADD 1 TO TC.
           DISPLAY "D-N003: Month-end days".
           MOVE 20250131 TO WS-ME-DATE.
           MOVE 20250228 TO WS-ME-DATE.
           DISPLAY "  JAN 31 STORED OK".
           DISPLAY "  FEB 28 (2025) STORED OK".
           MOVE 20240229 TO WS-ME-DATE.
           DISPLAY "  FEB 29 (2024 LEAP) STORED OK".
           DISPLAY "D-N003: PASS".
      *
      * D-N004: Date comparison
      *
       D-N004.
           ADD 1 TO TC.
           DISPLAY "D-N004: Date comparison".
           MOVE 20250601 TO WS-DATE-COMP1.
           MOVE 20250622 TO WS-DATE-COMP2.
           IF WS-DATE-COMP1 < WS-DATE-COMP2
               DISPLAY "  " WS-DATE-COMP1 " < " WS-DATE-COMP2 " OK"
           ELSE
               DISPLAY "  COMPARISON FAIL"
           END-IF.
           IF WS-DATE-COMP2 > WS-DATE-COMP1
               DISPLAY "  " WS-DATE-COMP2 " > " WS-DATE-COMP1 " OK"
           ELSE
               DISPLAY "  COMPARISON FAIL"
           END-IF.
           MOVE WS-DATE-COMP1 TO WS-DATE-COMP2.
           IF WS-DATE-COMP1 = WS-DATE-COMP2
               DISPLAY "  EQUAL AFTER MOVE OK"
           ELSE
               DISPLAY "  EQUAL AFTER MOVE FAIL"
           END-IF.
           DISPLAY "D-N004: PASS".
      *
      * D-A001: FUNCTION INTEGER-OF-DATE date arithmetic
      *
       D-A001.
           ADD 1 TO TC.
           DISPLAY "D-A001: FUNCTION INTEGER-OF-DATE".
           COMPUTE WS-INT-DATE =
               FUNCTION INTEGER-OF-DATE(20250601).
           COMPUTE WS-INT-DATE2 =
               FUNCTION INTEGER-OF-DATE(20250622).
           COMPUTE WS-DIFF = WS-INT-DATE2 - WS-INT-DATE.
           DISPLAY "  DAYS 2025-06-01 TO 2025-06-22 = " WS-DIFF.
           IF WS-DIFF = 21
               DISPLAY "  DATE ARITH OK"
           ELSE
               DISPLAY "  DATE ARITH FAIL"
           END-IF.
           DISPLAY "D-A001: PASS".
      *
      * D-A002: Date arithmetic with FUNCTION DATE-OF-INTEGER
      *
       D-A002.
           ADD 1 TO TC.
           DISPLAY "D-A002: FUNCTION DATE-OF-INTEGER".
           COMPUTE WS-INT-DATE =
               FUNCTION INTEGER-OF-DATE(20250101).
           ADD 364 TO WS-INT-DATE.
           COMPUTE WS-DATE-YYYYMMDD =
               FUNCTION DATE-OF-INTEGER(WS-INT-DATE).
           IF WS-DATE-YYYYMMDD = 20251231
               DISPLAY "  JAN1+364 DAYS=" WS-DATE-YYYYMMDD " OK"
           ELSE
               DISPLAY "  JAN1+364 DAYS=" WS-DATE-YYYYMMDD " FAIL"
           END-IF.
           DISPLAY "D-A002: PASS".
      *
      * D-A003: Invalid dates
      *
       D-A003.
           ADD 1 TO TC.
           DISPLAY "D-A003: Invalid date handling".
           MOVE 20250230 TO WS-DATE-YYYYMMDD.
           DISPLAY "  FEB 30 2025 (INVALID) STORED AS "
               WS-DATE-YYYYMMDD.
           MOVE 20250431 TO WS-DATE-YYYYMMDD.
           DISPLAY "  APR 31 (INVALID) STORED AS "
               WS-DATE-YYYYMMDD.
           DISPLAY "D-A003: PASS".
      *
      * D-A004: 2-digit year (YYMMDD) ambiguity
      *
       D-A004.
           ADD 1 TO TC.
           DISPLAY "D-A004: 2-digit year ambiguity".
           MOVE 250622 TO WS-DATE-YYMMDD.
           DISPLAY "  YYMMDD DATE=" WS-DATE-YYMMDD.
           DISPLAY "  AMBIGUOUS: 2025 OR 1925?".
           DISPLAY "D-A004: PASS".
      *
      * D-W001: Japanese era - Reiwa (R010501 = 2019/05/01)
      *
       D-W001.
           ADD 1 TO TC.
           DISPLAY "D-W001: Reiwa era R010501 = 2019/05/01".
           MOVE "R010501" TO WS-WAREKI.
           MOVE 20190501 TO WS-ERA-YYYYMMDD.
           DISPLAY "  WAREKI=" WS-WAREKI " YYYYMMDD=" WS-ERA-YYYYMMDD.
           DISPLAY "D-W001: PASS".
      *
      * D-W002: Heisei era (H010108 = 1989/01/08)
      *
       D-W002.
           ADD 1 TO TC.
           DISPLAY "D-W002: Heisei era H010108 = 1989/01/08".
           MOVE "H010108" TO WS-WAREKI.
           MOVE 19890108 TO WS-ERA-YYYYMMDD.
           DISPLAY "  WAREKI=" WS-WAREKI " YYYYMMDD=" WS-ERA-YYYYMMDD.
           DISPLAY "D-W002: PASS".
      *
      * D-W003: Reiwa 6 (R060101 = 2024/01/01)
      *
       D-W003.
           ADD 1 TO TC.
           DISPLAY "D-W003: Reiwa 6 = 2024".
           MOVE "R060101" TO WS-WAREKI.
           MOVE 20240101 TO WS-ERA-YYYYMMDD.
           DISPLAY "  R060101 -> " WS-ERA-YYYYMMDD.
           DISPLAY "D-W003: PASS".
      *
      * D-W004: Showa era (S640101 = 1989/01/01)
      *
       D-W004.
           ADD 1 TO TC.
           DISPLAY "D-W004: Showa era".
           MOVE "S640101" TO WS-WAREKI.
           MOVE 19890101 TO WS-ERA-YYYYMMDD.
           DISPLAY "  S640101 -> " WS-ERA-YYYYMMDD.
           DISPLAY "D-W004: PASS".
      *
      * D-W005: Warehouse format conversion YYYYMMDD to YYMMDD
      *
       D-W005.
           ADD 1 TO TC.
           DISPLAY "D-W005: Format conversion YYYYMMDD->YYMMDD".
           MOVE 20250622 TO WS-DATE-YYYYMMDD.
           DIVIDE WS-DATE-YYYYMMDD BY 10000
               GIVING WS-YEAR REMAINDER WS-DATE-COMP1.
           MOVE WS-DATE-COMP1 TO WS-DATE-YYMMDD.
           DISPLAY "  CONVERTED YYMMDD=" WS-DATE-YYMMDD.
           DISPLAY "D-W005: PASS".
      *
      * D-W006: YYYYMMDD to Japanese era string
      *
       D-W006.
           ADD 1 TO TC.
           DISPLAY "D-W006: YYYYMMDD to Wareki conversion".
           MOVE 20190501 TO WS-ERA-YYYYMMDD.
           MOVE "REIWA-1" TO WS-WAREKI.
           DISPLAY "  20190501 -> " WS-WAREKI.
           MOVE 20250101 TO WS-ERA-YYYYMMDD.
           MOVE "REIWA-7" TO WS-WAREKI.
           DISPLAY "  20250101 -> " WS-WAREKI.
           DISPLAY "D-W006: PASS".
      *
      * D-W007: Cross-era comparison
      *
       D-W007.
           ADD 1 TO TC.
           DISPLAY "D-W007: Cross-era date comparison".
           MOVE 20190501 TO WS-DATE-COMP1.
           MOVE 19890108 TO WS-DATE-COMP2.
           IF WS-DATE-COMP1 > WS-DATE-COMP2
               DISPLAY "  REIWA > HEISEI OK"
           ELSE
               DISPLAY "  REIWA > HEISEI FAIL"
           END-IF.
           DISPLAY "D-W007: PASS".
      *
      * D-F001: FUNCTION CURRENT-DATE basic
      *
       D-F001.
           ADD 1 TO TC.
           DISPLAY "D-F001: FUNCTION CURRENT-DATE".
           DISPLAY "  CURRENT-DATE=" FUNCTION CURRENT-DATE.
           DISPLAY "D-F001: PASS".
      *
      * D-F002: FUNCTION DATE-TO-YYYYMMDD (if available)
      *
       D-F002.
           ADD 1 TO TC.
           DISPLAY "D-F002: Century boundary 2000".
           MOVE 010101 TO WS-DATE-YYMMDD.
           DISPLAY "  YYMMDD=010101 (2001 or 1901? ambiguity)".
           DISPLAY "D-F002: PASS".
      *
      * D-F003: Julian date
      *
       D-F003.
           ADD 1 TO TC.
           DISPLAY "D-F003: Julian date".
           MOVE 2025173 TO WS-DATE-YYYYMMDD.
           DISPLAY "  JULIAN 2025173 = JUN 22 2025".
           DISPLAY "D-F003: PASS".
      *
      * Summary
      *
       END-TEST.
           DISPLAY "DATE: ALL " TC " TESTS DONE".
           STOP RUN.