IT公司100题-28-整数的二进制表示中1的个数

 1 #include <iostream>
 2 using namespace std;
 3 
 4 int calc(int num) {
 5     int count;
 6     while(num){
 7         count++;
 8         num = num & (num-1);
 9     }
10     return count;
11 }
12 
13 int main() {
14     cout << "input n: " << endl;
15     int n;
16     cin >> n;
17     int count = calc(n);
18     cout << "The num of 1 in " << n << " is: " << count << endl;
19     return 0;
20 }

$ ./a.exe
input n:
11
The num of 1 in 11 is: 3