题解 | #查找输入整数二进制中1的个数#

import java.util.; import java.io.;

public class Main{

public static void main(String[] args) {

    final InputStreamReader reader = new InputStreamReader(System.in);

    try (final BufferedReader br = new BufferedReader(reader)) {
        String str_number;
        while((str_number=br.readLine())!=null){
            int number = Integer.parseInt(str_number);
            String str= Integer.toBinaryString(number);
            String str2 =  str.replaceAll("[1]","");
            System.out.println(str.length() - str2.length());
        
        }



    }catch (IOException e ){
        System.out.println(e.getMessage());
    }
}

}