求int型正整数在内存中存储时1的个数

方法1:

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);

        int res=0;
        int x=sc.nextInt();
        while (x!=0){
            if ((x&1)==1){
                res++;
            }
            x=x>>1;
        }

        System.out.println(res);
    }
}

方法2:

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);

        int res=0;
        int x=sc.nextInt();
        String s=Integer.toBinaryString(x);
        for (int i=0;i<s.length();i++){
            if (s.charAt(i)=='1'){
                res++;
            }
        }

        System.out.println(res);
    }
}