第9讲6*

//法1
class Solution {
public:
    int NumberOf1(int n) {
        int res = 0;
        for (int i = 0; i < 32; i++)
        {
            if (n >> i & 1) res++;
        }
        return res;
    }
};

法2：lowbit
class Solution {
public:
    int NumberOf1(int n) {
        int res = 0;

        while (n) n -= n & -n, res++;

        return res;
    }
};