How to get position of right most set bit in C

Question

int a = 12;

for eg: binary of 12 is 1100 so answer should be 3 as 3rd bit from right is set.

I want the position of the last most set bit o

Answer 1

You can find the position of rightmost set bit by doing bitwise xor of n and (n&(n-1) )

int pos = n ^ (n&(n-1));