VB Snippet - Convert Decimal to Binary

[James Stanich]

Private Function DecToBin(ByVal Dec As Double) As Double
 
    Dim strTValue As String, strValue As String 
 
    Do
 
        strTValue = Str(Dec Mod 2)
 
        strValue= strTValue & strValue
 
        Dec = IIf(Right(Str(Dec), 2) = ".5", Dec - 0.5, IIf(Dec Mod 2 > 0, Dec - 1, Dec)) / 2
    
    Loop Until Dec = 0
    
    DecToBin = Val(strValue)
 
End Function

[CVMichael]

Nice... but for large numbers it returns something like: 1.001101011E+28 and I don't think anyone wants that...

I modified your code to return the number as a string, and the result is better

Private Function DecToBinStr(ByVal Dec As Double) As String
    Dim strTValue As String, strValue As String
    
    Do
        strTValue = Str(Dec Mod 2)
        strValue = strTValue & strValue
        
        Dec = IIf(Right(Str(Dec), 2) = ".5", Dec - 0.5, IIf(Dec Mod 2 > 0, Dec - 1, Dec)) / 2
    Loop Until Dec = 0
    
    DecToBinStr = Replace(strValue, " ", "")
End Function

Example of what i'm talking about

Debug.Print DecToBin(324534523)       ' returns 1.001101011E+28
Debug.Print DecToBinStr(324534523)  ' returns 10011010110000000000011111011