Here's some code that'll convert an integer to an arbitrary base up to 36, and convert a string representation of a base x value to an integer (given the base):
class Program {
static void Main(string[] args) {
int b10 = 123;
int targetBase = 5;
string converted = ConvertToBase(b10, targetBase);
int convertedBack = ConvertFromBase(converted, targetBase);
string base3 = "212210";
string base7 = ConvertFromBaseToBase(base3, 3, 7);
Console.WriteLine(converted);
Console.WriteLine(convertedBack);
Console.WriteLine(base7);
Console.ReadLine();
}
private const string chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
private static string ConvertToBase(int b10, int targetBase) {
if (targetBase < 2) throw new ArgumentException("Target base must be greater than 2.", "targetBase");
if (targetBase > 36) throw new ArgumentException("Target base must be less than 36.", "targetBase");
if (targetBase == 10) return b10.ToString();
StringBuilder result = new StringBuilder();
while (b10 >= targetBase) {
int mod = b10 % targetBase;
result.Append(chars[mod]);
b10 = b10 / targetBase;
}
result.Append(chars[b10]);
return Reverse(result.ToString());
}
private static int ConvertFromBase(string bx, int fromBase) {
if (fromBase < 2) throw new ArgumentException("Base must be greater than 2.", "fromBase");
if (fromBase > 36) throw new ArgumentException("Base must be less than 36.", "fromBase");
if (fromBase == 10) return int.Parse(bx);
bx = Reverse(bx);
int acc = 0;
for (int i = 0; i < bx.Length; i++) {
int charValue = chars.IndexOf(bx[i]);
acc += (int)Math.Pow(fromBase, i) * charValue;
}
return acc;
}
public static string ConvertFromBaseToBase(string bx, int fromBase, int toBase) {
int b10 = ConvertFromBase(bx, fromBase);
return ConvertToBase(b10, toBase);
}
public static string Reverse(string s) {
char[] charArray = new char[s.Length];
int len = s.Length - 1;
for (int i = 0; i <= len; i++)
charArray[i] = s[len - i];
return new string(charArray);
}
}
If you're unconcerned with displaying these values, you can use extended characters in your chars set - if you stick to plain ascii, you can theoretically have base256 values. Going beyond that I would recommend not using chars, but instead using some other uniquely-identifiable value - though I don't much see the value.