# Base Conversion Pro

The function BaseConv convert any base 10 numbers to any selected base (max 64) and the function ConvBase10 convert it back to base 10.

It can be useful for cryptography purpose example: convert the ASCII value of a char to a secret base...or it can be useful for any algorithm that returns numbers and that you want as a string. The maximum base could be extended by adding other characters to the constant DIGITS. With the original DIGITS this algorithm is compatible for conversion to common base: Binary (2), Hex (16), Octal (8).

**Original Author:** Vincent Bouret

### Inputs

Use: BaseConv(base10_original_number, newbase)

to convert in a particular base

Or use: ConvBase10(otherbase_number, oldbase)

### Assumptions

Juste paste the code anywhere.

### Returns

BaseConv returns a string and ConvBase10 return a long integer

### Side Effects

If you add char to DIGITS (to extend the base maximum) be aware to avoid adding the same char twice or else you will get an error.

### Code

`'Use: BaseConv(base10_original_number, newbase)`

'to convert in a particular base

'Or use: ConvBase10(otherbase_number, oldbase)

Const ZERO = "0"

Const DIGITS = "123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz/.="

Function ConvBase(n1 As Double, base As Long) As String

Dim e2(30) As Double

Dim n As Integer

Dim i As Long

Dim max As Long

If base > Len(DIGITS) Then ConvBase = "NULL": Exit Function

If n1 = 1 Then ConvBase = "1": Exit Function

n = 0

Do While (base ^ n) <= n1

n = n + 1

Loop

n = n - 1

i = 0

Do While n > -1

e2(i) = n1 (base ^ n)

n1 = n1 Mod (base ^ n)

n = n - 1

i = i + 1

Loop

max = i - 1

For i = 0 To max

If e2(i) = 0 Then

ConvBase = ConvBase & ZERO

Else

ConvBase = ConvBase & Mid(DIGITS, e2(i), 1)

End If

Next i

End Function

Function ConvBase10(num As String, base As Long) As Double

Dim i As Long

Dim n As Long

n = Len(num)

For i = 1 To n

If Mid(num, i, 1) <> ZERO Then

ConvBase10 = ConvBase10 + (InStr(1, DIGITS, Mid(num, i, 1)) * (base ^ (n - i)))

End If

Next i

End Function

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