整数的二进制表示中1的个数

#include<iostream>
using namespace std;
int count_one_1(int num){
int cnt=0;
//unsigned int i=1;
int i=1;
while(i){
if(num&i) cnt++;
i=i<<1;
}
return cnt;
}
int count_one_2(int num){      //很赞的方法
int cnt=0;
while(num){
num=num&(num-1);       //101 & 100 = 100; 100 & 011=0;
cnt++;
}
return cnt;
}
int main(void){
int num;
while(cin>>num){
cout<<"solution1:" <<count_one_1(num)<<endl;
cout<<"solution2:" <<count_one_2(num)<<endl;
}
system("pause");
return 0;
}