코드업(Codeup) 1920 : (재귀함수) 2진수 변환

import java.util.Scanner;

public class Main {
    static String rs = "";

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

        int num = sc.nextInt();
        Start(num);
        System.out.println(rs);
    }  

    public static void Start(int num) {
        rs = num % 2 + rs;

        num = num / 2;

        if(num >= 1) {
            Start(num);
        }
    }
}