Why use hex?

Question

Hey! I was looking at this code at http://www.gnu.org/software/m68hc11/examples/primes_8c-source.html

I noticed that in some situations they used hex numbers, like i

Answer 1

Generally the use of Hex numbers instead of Decimal it's because the computer works with bits (binary numbers) and when you're working with bits also is more understandable to use Hexadecimal numbers, because is easier going from Hex to binary that from Decimal to binary.

OxFF = 1111 1111 ( F = 1111 )

but

255 = 1111 1111 

because

255 / 2 = 127 (rest 1)
127 / 2 = 63 (rest 1)
63 / 2 = 31 (rest 1)
... etc

Can you see that? It's much more simple to pass from Hex to binary.