题解 | #查找输入整数二进制中1的个数#

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner fzhinput = new Scanner(System.in);
        String erjz;
        Long num;
        int sum;
        while (fzhinput.hasNextLine()){
            num = fzhinput.nextLong();
            fzhinput.nextLine();
            erjz = Long.toString(num, 2);
            sum = 0;
            for (int i = 0; i < erjz.length(); i++) {
                if (erjz.charAt(i) == '1') {
                    sum++;
                }
            }
            System.out.println(sum);
        }
    }
}