DATE AND AGE VALIDATION IN COBOL

USEFUL THINGS IN COBOL

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SOME USEFUL  THINGS

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COMPUTE DDN = FUNCTION NUMVAL (DD).
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NUMVAL CONVERTS CHARACTERS TO NUMBERS
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IF
DIVIDE CCYY BY 4 GIVING CCYY REMAINDER CCYY
DISPLAY 'LEAP YEAR'.
END-IF.
DISPLAY CCYY.

MOVE FUNCTION DATE-OF-INTEGER (DATEINTEGER) TO DATENUMBER.
DISPLAY DATENUMBER.
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1600 DEC 31 GREGORIAN
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IDENTIFICATION DIVISION.
PROGRAM-ID. DATE.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 DATENUMBER PIC 9(8).
01 DATEINTEGER PIC 9(8).
PROCEDURE DIVISION.
MOVE 20170914 TO DATENUMBER.
IF DATENUMBER IS NOT NUMERIC
              DISPLAY 'NOT NUMBER'
ELSE
              MOVE FUNCTION INTEGER-OF-DATE (DATENUMBER) TO DATEINTEGER.
    IF DATEINTEGER EQUAL ZERO
              DISPLAY 'DATE IS INVALID'
    ELSE
              COMPUTE DATENUMBER = FUNCTION NUMVAL (FUNCTION CURRENT-DATE(1:8)) - DATENUMBER
        IF DATENUMBER(1:4) < 20 OR > 60
              DISPLAY 'AGE IS LESSTHAN 20 OR GREATERTHAN 60'
END-IF.
STOP RUN.
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