191. Number of 1 Bits

class Solution {
public:
    int hammingWeight(uint32_t n) {
        int res = 0;
        while(n)
        {
            if(n%2) res++;
            n /= 2;
        }
        return res;
    }
};

class Solution {
public:
    int hammingWeight(uint32_t n) {
        int bits = 0;
        int mask = 1;
        for(int i=0; i<32; i++)
        {
            if(n&mask) bits++;
            mask *=2;
        }
        return bits;
    }
};