Here’s a function that converts a decimal number (base 10) to another base number system. Each digit position corresponds to a power of N, where N is a number between 2 and 36. In other words, if a number system’s base is N, then N digits are used to write numbers in that system. For example, the base 2 number system (binary) uses the digits 0 and 1, while the base 20 system uses digits 0 through K.
The ConvertDecToBaseN function accepts a double-value decimal number and a byte-value representing the base number between 2 and 36. By default, the base value used is 16 (hexadecimal). The decimal number is converted to a positive number if it’s negative. This function is useful for representing large numbers as strings, using fewer digit positions. I developed it to help reduce the footprint of several large numbers used in constructing a 16-character unique string ID. (Creating a complementary function to convert a base N number back into a decimal would be a great exercise.)
Public Function ConvertDecToBaseN(ByVal dValue As Double, _ Optional ByVal byBase As Byte = 16) As String Const BASENUMBERS As String = _ "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" Dim sResult As String Dim dRemainder As Double On Error GoTo ErrorHandler sResult = "" If (byBase < 2) Or (byBase > 36) Then GoTo Done dValue = Abs(dValue)Do dRemainder = dValue - (byBase * Int((dValue / byBase))) sResult = Mid$(BASENUMBERS, dRemainder + 1, 1) & sResult dValue = Int(dValue / byBase)Loop While (dValue > 0)Done: ConvertDecToBaseN = sResult Exit FunctionErrorHandler: Err.Raise Err.Number, "ConvertDecToBaseN", _ Err.DescriptionEnd FunctionSample usage:ConvertDecToBaseN(999999999999#, 36)'Returns 'CRE66I9R
