LeetCode Number of 1 Bits 计算1的个数

 1 class Solution {
 2 public:
 3     int hammingWeight(uint32_t n) {
 4         if(!n) return 0;
 5         if(n==1) return 1;
 6         
 7         uint32_t MASK = 1, temp=n;
 8         int i, cnt = 0;
 9         for(i=0; i<32; i++)
10         {
11            if( temp & MASK )
12                 cnt++;
13             temp = temp>>1;
14         }
15         return cnt;
16     }
17 };