half an int

Hello all, just a quick quest:

is half an unsigned int 0x80000000 or 0x7FFFFFFF?

0xFFFFFFFF / 2 = 0x7FFFFFFF

but

0x7FFFFFFF * 2 = 0xFFFFFFFE

(note the trailing E)

and

0x80000000 * 2 = 0x0 (or more exactly 0x100000000 (9 digits))

I opt for 0x7FFFFFFF (as 2 * the half shouldnt be 0!)

Any comments or thoughts?

0x7FFFFFFF

would be "half" of an unsigned 32 bit integer, though "half" is a rather silly term for it. A 32 integer holds an even number of values, but you have to remember that the values start at 0 not 1, so dividing directly by 2 will give you a fraction. What you'd do is divide 2^32 by 2 and then subtract 1 from it to get "half" full. Since the "value" of 0xFFFFFFFF is odd, you can't multiply an integer by 2 to get it.

The reason you are getting 0 for 0x80000000 * 2 is because that goes 1 over the maximum amount that a 32 bit integer can hold. The numbers "rolled over" back to 0.