题解 | #查找输入整数二进制中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);
        while (in.hasNextInt()) {
            int num = in.nextInt();
            String s = Integer.toBinaryString(num);
            int count = 0;
            for (int i = 0; i < s.length(); i++) {
                if (s.charAt(i) == '1') {
                    count++;
                }
            }
            System.out.println(count);
        }
    }
}