题解 | #求int型正整数在内存中存储时1的个数#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int num = in.nextInt();
        int one = 1;
        int cnt = 0;
        
        for (int i = 0; i < 32; i++) {
            if ((num & one) == 1) {
                cnt++;
            }
            num = num >> 1;
        }
        System.out.print(cnt);
    }
}