问题：

之前做过类似题，但这次仍然不能解决相关问题。

字符串倒过来输：StringBuffer str=new StringBuffer(s); s=str.reverse().toString()

Bitset

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)

Problem Description

Give you a number on base ten,you should output it on base two.(0 < n < 1000)

Input

For each case there is a postive number n on base ten, end of file.

Output

For each case output a number on base two.

Sample Input

1
2
3

Sample Output

1
10
11

代码：

import java.util.*;

public class Main{
	public static void main(String args[]){
		Scanner cin=new Scanner(System.in);
		while(cin.hasNext()){
			int n=cin.nextInt();
			String s="";
			while(n!=0){
				s=s+(n%2);
				n=n/2;
			}
			StringBuffer str=new StringBuffer(s);
			s=str.reverse().toString();
			System.out.println(str);
		}
	}
}