java多用例输入

import java.util.Scanner;

public class sum {
public  static void main(String[] arg)
{
int n;
float num1,num2,num;
String op;
Scanner in=new Scanner(System.in);//定义输入流
while(in.hasNext()){           //多用例主要就是这个in.hasNext();
n=in.nextInt();
System.out.println(n);
}
}

}