题解 | #求int型正整数在内存中存储时1的个数#

import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int a = scanner.nextInt();
        String s = Integer.toBinaryString(a);
        int res = 0;
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == 49) {
                res++;
            }
        }
        System.out.println(res);
    }
}