Answer by Chethan for How to check if a number is a power of 2

Here is another method I devised, in this case using | instead of & :

bool is_power_of_2(ulong x) {    if(x ==  (1 << (sizeof(ulong)*8 -1) ) return true;    return (x > 0) && (x<<1 == (x|(x-1)) +1));}