Does anyone have a way to determine if a number is odd or even? En taro Adun! Doom to all who threaten the homeworld! *Protoss Zealot - Starcraft*

Test if the first bit is set. If it is set then the number is odd, otherwise it is even.

A number n (I''ll stick to integers) is even if n mod 2 = 0, and odd if n mod 2 = 1 (these are the only two possibilities, so of course the first test can just be negated for odd). In C (for example), this is n%2 == 0 (even), or n%2 == 1 (odd).

Miles

yes,

one method is:

if (number MODULO 2) == 1
then
number is odd.

in C++:

if ((number % 2) == 1)
cout << "number is odd";



schiggl

Thanks!

En taro Adun!
Doom to all who threaten the homeworld!
*Protoss Zealot - Starcraft*

um... Miles... don''t the terms odd and even only make sense in relation to integers?

Anyho, the bit test is mucho faster than using modulus, so stick to that.

Mathematically speaking, they do.

But a float can have a value 2.
so it would be a "integer" in mathamatics

Bugle4d

will the bit test also work with signed integers? negative numbers have inverted bits (2s complement).

a2k

Yes, it will work for negative integers also. Any positive even number will have the LSB set to 0. To negate this number using two''s complement, first invert all bits; LSB is now 1. Then you add one, and turn this one into a zero again.