Broken IntToCharArray()

private static char[] IntToCharArray(int input)
{
     short len = 0; //Number of places in the integer
     if(input < 10) len = 1;
     else if(input < 100) len = 2;
     else if (input < 1000) len = 3;
     else if (input < 10000) len = 4;
     else return null; // We just don't support those bigger numbers

     char[] output = new char[len];
     int input_copy = input;
     int i = 0;

     while (len > 0)
     {
         // 48 is just the offset in the ASCII table of the character
         // '0', so if we add 0-9 to that index, we can get the
         //characters for 0-9.
         output[i++] = (char)(48+(input%10));
         input-=(10^len);
         len--;
     }
     return output;
}