题目：

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.

提示：

考察的是程序递归调用，以及对二进制表示的理解。

代码：

class Solution {
public:
    int hammingWeight(uint32_t n) {
        if (!n) return 0;
        return (n % 2) + hammingWeight(n >> 1);
    }
};

【LeetCode】Number of 1 Bits

原文：http://www.cnblogs.com/jdneo/p/4738942.html