Numerical Conversion - Multiple Bases

[Torc]

Hi All,

I was looking at the problem of developing a routine to convert between a
number of different bases - 2, 4, 8, 10, 16 etc.

I came up with the following which seems to work fine, can anyone come up with a better way?

Option Explicit
Private Const NumStr = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
Function Convert(ByVal Value As Long, ByVal Base As Long) As String
Dim NumVal As Long
Dim Answer As String
Dim Negative As Boolean
    If (Base < 2) Or (Base > 36) Then
        Convert = "#BASE ERROR#"
    Else
        If Value < 0 Then
            Negative = True
            Value = -Value
        Else
            Negative = False
        End If
        Answer = ""
        Do
            If Value = 0 Then
                Exit Do
            End If
            NumVal = (Value Mod Base) + 1
            Answer = Mid(NumStr, NumVal, 1) & Answer
            Value = Value \ Base
        Loop
        If Negative Then
            Answer = "-" & Answer
        End If
        Convert = Answer
    End If
End Function
Function ConvertBack(ByVal Value As String, ByVal Base As Long) As Long
Dim NumVal As Long
Dim Answer As Long
Dim Pos As Long
Dim Negative As Boolean
    If (Base < 2) Or (Base > 36) Then
        ConvertBack = 0
    Else
        Answer = 0
        If Left(Value, 1) = "-" Then
            Pos = 2
            Negative = True
        Else
            Negative = False
            Pos = 1
        End If
        Do
            If Pos > Len(Value) Then
                Exit Do
            End If
            NumVal = InStr(1, NumStr, Mid(Value, Pos, 1)) - 1
            Answer = (Answer * Base) + NumVal
            Pos = Pos + 1
        Loop
        If Negative Then
            Answer = -Answer
        End If
        ConvertBack = Answer
    End If
End Function