Help with DATE$

 BBS: Inland Empire Archive
Date: 04-09-92 (08:07)             Number: 108
From: MATT HART                    Refer#: NONE
  To: GRAHAM CHATFIELD              Recvd: NO  
Subj: Help with DATE$                Conf: (2) Quik_Bas

 GC> What I need is a date calculator to perform a function like this:

 GC> Take todays date (April 7/92) which date$ prints as "04-07-1992"
 GC> and find the new date if I subtract 20 days from todays date.

 GC> IE:    DATE$ - number_of_days = previous date

 GC>  or   April 7/92 - 20 = March xx/92

' ADDDATE.BAS  Matt Hart
'
' OldDate$ in format MM-DD-YYYY
'
DEFINT A-Z
DECLARE FUNCTION AddDate$(OldDate$,NumDays)

INPUT NumDays
IF NumDays => 0 THEN
    PRINT Date$+" +";NumDays;" = ";AddDate$(Date$,NumDays)
ELSE
    PRINT Date$+" ";NumDays;" = ";AddDate$(Date$,NumDays)
ENDIF
END

FUNCTION AddDate$(OldDate$,NumDays)
    MM = VAL(LEFT$(OldDate$,2))
    DD = VAL(MID$(OldDate$,4,2))
    YY = VAL(RIGHT$(OldDate$,4))
    DD = DD + NumDays
    LeapYear = -(YY <> 2000 AND YY MOD 4 = 0)
    DO UNTIL DD > 0
        SELECT CASE MM
            CASE 1
                DD = DD + 31
                YY = YY - 1
                MM = 12
                LeapYear = -(YY <> 2000 AND YY MOD 4 = 0)
            CASE 2,4,6,8,9,11
                DD = DD + 31
                MM = MM - 1
            CASE 3
                DD = DD + 28 + LeapYear
                MM = MM - 1
            CASE 5,7,10,12
                DD = DD + 30
                MM = MM - 1
        END SELECT
    LOOP
    DO
        SELECT CASE MM
            CASE 1,3,5,7,8,10
                IF DD > 31 THEN
                    MM = MM + 1
                    DD = DD - 31
                ELSE
                    EXIT DO
                ENDIF
            CASE 2
                IF DD > 28+LeapYear THEN
                    MM = MM + 1
                    DD = DD - 28 - LeapYear
                ELSE
                    EXIT DO
                ENDIF
            CASE 4,6,8,9,11
                IF DD > 31 THEN
                    MM = MM + 1
                    DD = DD - 30
                ELSE
                    EXIT DO
                ENDIF
            CASE 12
                IF DD > 31 THEN
                    MM = 1
                    DD = DD - 31
                    YY = YY + 1
                    LeapYear = -(YY <> 2000 AND YY MOD 4 = 0)
                ELSE
                    EXIT DO
                ENDIF
        END SELECT
    LOOP
    M$ = LTRIM$(RTRIM$(STR$(MM))) : IF MM<10 THEN M$="0"+M$
    D$ = LTRIM$(RTRIM$(STR$(DD))) : IF DD<10 THEN D$="0"+D$
    Y$ = LTRIM$(RTRIM$(STR$(YY)))
    AddDate$ = M$+"-"+D$+"-"+Y$
END FUNCTION

---
 * Origin: Midnight Micro!  V.32/REL  (918)451-3306 (1:170/600)