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.

题解：很简单，一位一位的和1做"与"运算就好。

class Solution {

public:

    int hammingWeight(uint32_t n) {

        int ans=;

        while(n>){

            ans+=((n&)==?:);

            n>>=;

        }

        return ans;

    }

};