题解 | 求int型正整数在内存中存储时1的个数

#include <bits/stdc++.h>
using namespace std;
int main() {
    int a ;
    cin >> a;
    if (a == 0) cout << "0";
    string b;
    while (a > 0) {
        b += (a % 2) ? "1" : "0"; // 取余数并转换为字符
        a /= 2;
    }
    //reverse(b.begin(), b.end()); 如用于输出二进制，则需要这行代码
    int c = 0;
    for (int i = 0; i < b.length(); i++) {
        if (b[i] == '1') {
            c = c + 1;
        }
    }
    cout << c;
    return 0;
}