191. number of 1 bits

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.

1
2
3
4
5
6
7
8
9
10
11

class  {
public:
    int hammingWeight(uint32_t n) {
        int count=0;
            while(n){
                count+=n&1;
                n>>=1;
            }
        return count;
    }
};