191. Number of 1 Bits (Int; Bit)

Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight).

For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011, so the function should return 3.

class Solution {
public:
    int hammingWeight(uint32_t n) {
        int ret = 0;
        for (unsigned int i = 1; i != 0; i <<= 1){
            if(n & 1) ret++;
            n >>= 1;
        }
        return ret;
    }
};