题解 | 十进制数转二进制数

import java.util.*;

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

        //write your code here......
	  //不确定二进制有几位，那就先计算出位数，然后将一个个计算出来的余数存入数组，再从数组中遍历出来组成一个多位数
        int a=num;
        int result=0;
        int b;
        int count=0;
       
      while(a>0){
a=a/2;
count++;
      }
      a=num;
       int []arr=new int[count];
      for(int i=0;i<count;i++){
      b=a%2;
      arr[i]=b;
      a=a/2;
      } for(int i=count-1;i>=0;i--){
      result=arr[i]+10*result;
      }
      

        
        System.out.print(result);

    }
}