Gregorian calendar leap year check

       IDENTIFICATION DIVISION.
       PROGRAM-ID. program.

       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 example.
           02 year                      PIC 9(4).
           02 FILLER                    PIC X VALUE " ".
           02 result                    PIC X.

       PROCEDURE DIVISION.
           MOVE 1000 TO year
           CALL "is-leap-year" USING year, result
           DISPLAY example

           MOVE 2000 TO year
           CALL "is-leap-year" USING year, result
           DISPLAY example

           MOVE 2004 TO year
           CALL "is-leap-year" USING year, result
           DISPLAY example

           MOVE 2016 TO year
           CALL "is-leap-year" USING year, result
           DISPLAY example

           MOVE 2017 TO year
           CALL "is-leap-year" USING year, result
           DISPLAY example

           STOP RUN
           .

       END PROGRAM program.

       IDENTIFICATION DIVISION.
       PROGRAM-ID. is-leap-year.

       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 by-4                          PIC 9(4) COMP.
       01 by-100                        PIC 9(4) COMP.
       01 by-400                        PIC 9(4) COMP.

       LINKAGE SECTION.
       01 year                          PIC 9(4).
       01 result                        PIC X.

       PROCEDURE DIVISION USING year, result.
           COMPUTE by-4   = FUNCTION mod(year, 4)
           COMPUTE by-100 = FUNCTION mod(year, 100)
           COMPUTE by-400 = FUNCTION mod(year, 400)
           IF by-4 = 0 AND (by-100 <> 0 OR by-400 = 0) THEN
               MOVE 'Y' TO result
           ELSE
               MOVE 'N' TO result
           END-IF
           EXIT PROGRAM
           .

       END PROGRAM is-leap-year.