Good point, I actually thought of doing that and then dismissed it. Maybe the best perfoming way would be to use the remainder as the index to an array (suggested in another comment)?
1. The standard library C function atoi may be named 'ASCII to integer', but it should convert a numerical string in the platform's encoding to integer. For symmetry, itoa should convert an integer to a platform encoded numeric string, not to an ASCII numerical string.
2. Not all computers use ASCII for C strings. Because of that, '0' need not equal 0x30. For example, in EBCDIC, one has '0' == 0xF0.
Utterly pedantic: IIRC, the C standard guarantees that '0' through '9' are contiguous and in order. If you know better, or aren't sure, use "0123456789"[i] to convert a 0...9 value to the corresponding char.
