Every bit aside for the ones bit is even. All you have to do is get the ones bit(the far right) for it being a 1 or 0. Which is the fastest and least amount of code needed.
use bitwise &
<span style="color:#323232;">// n&1 is true, then odd, or !n&1 is true for even
</span><span style="color:#323232;">
</span><span style="color:#323232;"> return (!(n & 1));
</span>