Date functions

[dano]

For date difference calculations why not convert to Julian and get the difference?

Code: (Select All)

Start:
Input "Date1: ", d1$
If d1$ = "" Then System
Input "Date2: ", d2$
Print "Difference in days: "; Julian#(d2$) - Julian#(d1$)
Print: Print: Print
GoTo Start
 
 
 
Function Julian# (from$)
    'Gives # of days since Monday, January 1, 4713 BC
    'accepts xx-xx-xxxx OR xx/xx/xxxx OR xx-xx-xx OR xx/xx/xx
 
    'from$ must be either 8 or 10 characters
    If Len(from$) <> 8 And Len(from$) <> 10 Then Julian# = 0: Exit Function
 
    'must be xx-xx or xx/xx format
    If Mid$(from$, 3, 1) <> "-" And Mid$(from$, 3, 1) <> "/" Then Julian# = 0: Exit Function
    If Mid$(from$, 6, 1) <> "-" And Mid$(from$, 6, 1) <> "/" Then Julian# = 0: Exit Function
 
    Month% = Val(Mid$(from$, 1, 2))
    Day% = Val(Mid$(from$, 4, 2))
    If Len(from$) = 10 Then
        Year% = Val(Right$(from$, 4))
    ElseIf Len(from$) = 8 Then
        Year% = Val("20" + Right$(from$, 2))
    End If
 
    Select Case Month%
        Case Is >= 3
            Month% = Month% - 3
        Case Is <= 2
            Month% = Month% + 9
            Year% = Year% - 1
    End Select
 
    A# = 146097# * Fix(Fix(Year% / 100) / 4)
    B# = Fix(1461# * (Year% Mod 100) / 4)
    C# = Fix((153# * Month% + 2) / 5) + Day% + 1721119
 
    Julian# = A# + B# + C#
End Function