random even number in Objective-C? -

i know :

randnum = arc4random_uniform(n);

will set randnum random number 0 n - 1.

however how can modify above statement random number 0 n - 1?

it faster using bitwise operator, clear lowest bit @gallymon said.

unsigned int evennumber = arc4random_uniform(n) & 0xfffffffe ;

My