Quellcode-Bibliothek easter.cob   Sprache: Cobol

       IDENTIFICATION DIVISION.
      *
       PROGRAM-ID.    EASTER.
      *
       DATE-WRITTEN.  08/30/98.
      *
      *           Calculate Date of Easter.
      *
      *        *******************************
      *        *                             *
      *        *     Judson D. McClendon     *
      *        *     Sun Valley Systems      *
      *        *     4522 Shadow Ridge Pkwy  *
      *        *     Pinson, AL 35126-2192   *
      *        *        205-680-0460         *
      *        *                             *
      *        *******************************
      *
       ENVIRONMENT DIVISION.
      *
       DATA DIVISION.
      *
       WORKING-STORAGE SECTION.
      *
      *
      *
      ******************************************************************
      *                                                                *
      *                 E A S T E R   W O R K   A R E A                *
      *                                                                *
      ******************************************************************
      *
       01  EASTER-WORK-AREA.
           03  EW-DATE                 PIC  9(08) VALUE ZEROS.
           03  EW-DATE-X               REDEFINES EW-DATE.
               05  EW-YEAR                 PIC  9(04).
               05  EW-MONTH                PIC  9(02).
               05  EW-DAY                  PIC  9(02).
           03  EW-GOLDEN-NBR           PIC  9(06).
           03  EW-CENT                 PIC  9(03).
           03  EW-LEAP-CENT            PIC  9(06).
           03  EW-LUNAR-CORR           PIC  9(08).
           03  EW-SUNDAY-CORR          PIC  9(08).
           03  EW-EPACT                PIC  9(08).
           03  EW-FULL-MOON            PIC  9(08).
           03  EW-WORK1                PIC  9(08).
           03  EW-WORK2                PIC  9(08).
           03  EW-MONTH-NAMES      VALUE
                               "JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC".
               05  EW-MONTH-NAME       OCCURS 12 TIMES
                                           PIC  X(03).
      *
       PROCEDURE DIVISION.
      *
      *
       000000-CONTROL.
      *
           DISPLAY "ENTER YEAR FOR EASTER".
           ACCEPT EW-YEAR.
      *
           PERFORM 001000-EASTER-CALC
              THRU 001000-EXIT.
      *
           DISPLAY "EASTER FALLS ON "
                   EW-MONTH-NAME(EW-MONTH)
                   " "
                   EW-DAY.
      *
       000000-EXIT.
           STOP RUN.
      *
      *
      *
      ******************************************************************
      *                                                                *
      *                    E A S T E R   C A L C                       *
      *                                                                *
      *                                                                *
      *    CALCULATES THE DATE OF EASTER FOR ANY DATE IN THE           *
      *    GREGORIAN CALENDAR.                                         *
      *                                                                *
      *    USAGE:  MOVE <EASTER YEAR> TO EW-YEAR.                      *
      *            PERFORM 001000-EASTER-CALC                          *
      *               THRU 001000-EXIT.                                *
      *                                                                *
      *    RESULT: EW-DATE = DATE OF EASTER IN YYYYMMDD FORM.          *
      *                                                                *
      ******************************************************************
      *
       001000-EASTER-CALC.
      *
      **** COMPUTE EW-GOLDEN-NBR =
      ****     FUNCTION REM (EW-YEAR, 19) + 1.
           DIVIDE 19 INTO EW-YEAR GIVING EW-WORK1
               REMAINDER EW-GOLDEN-NBR.
           ADD 1 TO EW-GOLDEN-NBR.
      *
           COMPUTE EW-CENT =
               (EW-YEAR / 100) + 1.
      *
           COMPUTE EW-LEAP-CENT =
               ((3 * EW-CENT) / 4) - 12.
      *
           COMPUTE EW-LUNAR-CORR =
               ((8 * EW-CENT + 5) / 25) - 5.
      *
           COMPUTE EW-SUNDAY-CORR =
               ((5 * EW-YEAR) / 4) - EW-LEAP-CENT - 10.
      * 
      **** COMPUTE EW-EPACT =
      ****     FUNCTION REM ((11 * EW-GOLDEN-NBR + 20 
      ****                    + EW-LUNAR-CORR - EW-LEAP-CENT), 30).
           COMPUTE EW-EPACT =
               11 * EW-GOLDEN-NBR + 20 + EW-LUNAR-CORR - EW-LEAP-CENT.
           DIVIDE 30 INTO EW-EPACT GIVING EW-WORK1
               REMAINDER EW-EPACT.
      * 
           IF (EW-EPACT = 24)
               OR
              ( (EW-EPACT = 25)
                 AND
                (EW-GOLDEN-NBR > 11) )
               ADD 1 TO EW-EPACT.
      *
           COMPUTE EW-FULL-MOON = 44 - EW-EPACT.
           IF (EW-FULL-MOON < 21)
               ADD 30 TO EW-FULL-MOON.
      * 
      **** COMPUTE EW-DAY =
      ****     EW-FULL-MOON + 7
      ****         - FUNCTION REM ((EW-SUNDAY-CORR + EW-FULL-MOON), 7).
           ADD EW-SUNDAY-CORR EW-FULL-MOON GIVING EW-WORK1.
           DIVIDE 7 INTO EW-WORK1 GIVING EW-WORK2
               REMAINDER EW-WORK1.
           COMPUTE EW-DAY =
               EW-FULL-MOON + 7 - EW-WORK1.
      *
           IF (EW-DAY > 31)
               MOVE 4 TO EW-MONTH
               SUBTRACT 31 FROM EW-DAY
           ELSE
               MOVE 3 TO EW-MONTH.
           MOVE EW-YEAR TO EW-YEAR.
      *
       001000-EXIT.
           EXIT.