Day of Week Function

Category:

Dates and Math

Type:

Snippets

Difficulty:

Beginning

Author:

neophile

Version Compatibility: Visual Basic 6, Visual Basic 5

More information:

This is exactly like VB's Weekday function, except it's return range of 0 (Sunday) - 6 (Saturday), instead of 1-7.

This code can even be adapted to a calculator with programming capability. In fact, I first wrote this years ago on a TI-85 :)

Instructions: Copy the declarations and code below and paste directly into your VB project.

Declarations:
' None

Code:

Public Function DOW(ByVal GregDate As Date) As String
' Return values:
' 0 = Sunday
' 1 = Monday
' 2 = Tuesday
' 3 = Wednesday
' 4 = Thursday
' 5 = Friday
' 6 = Saturday
    Dim y As Integer
    Dim m As Integer
    Dim d As Integer
    
    ' monthdays:
    ' This is a "template" for a year. Each number
    ' stands for a day of the week. The general idea
    ' is that, in a standard year, if Jan 1 is on a
    ' Friday, then Feb 1 will be a Monday, Mar 1
    ' will be a Monday, April 1 will be a Thursday,
    ' May 1 will be Saturday, etc..
    Dim mcode As String
    Dim monthdays() As String
    monthdays = Split("5 1 1 4 6 2 4 0 3 5 1 3")
    
    ' Grab our date info
    y = Val(Format(GregDate, "yyyy"))
    m = Val(Format(GregDate, "mm"))
    d = Val(Format(GregDate, "dd"))
    
    ' Snatch the corresponding month code
    mcode = Val(monthdays(m - 1))
    
    ' Multiplying by 1.25 takes care of leap years,
    ' but not completely. Jan and Feb of a leap year
    ' will end up a day extra.
    ' The 'mod 7' gives us our day.
    DOW = ((Int(y * 1.25) + mcode + d) Mod 7)
    
    ' This takes care of leap year Jan and Feb days.
    If y Mod 4 = 0 And m < 3 Then DOW = (DOW + 6) Mod 7
End Function