题解 | 二进制中有多少个1

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 scanner = new Scanner(System.in);
        if (scanner.hasNextInt()) {
            int num = scanner.nextInt();
            int count = 0;
            while (num > 0) {
                count += (num & 0x01);
                num = num >> 1;
            }
            System.out.println(count);
        }
        scanner.close();
    }
}