1.描述

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.

2.分析

3.代码

int hammingWeight(uint32_t n) {
    unsigned int result = 0;
    for (unsigned int i = 0; i < 32; ++i) {
        result += n & 0x1;
        n >>= 1;
    }
    return result;
}