01-28-2009, 06:33 PM

The 0x prefix tells the compiler that the number value "ffff" is given in base 16 (hexadecimal) rather than base 10 (decimal). In hexadecimal, A through F are digits just like 0 through 9.

To understand this better, I recommend reading at least the first 1/3 or so of the

Wikipedia page on hexadecimal.