10月31日lab1

package pan;
import javax.swing.JOptionPane;
public class pan1{

public static void main(String[] args)
{int x=1;
int n=1;
while(n>=0){
String a = JOptionPane.showInputDialog("打一個數字");
n = Integer.parseInt(a);
if (n>=0) x*=n;
}
System.out.println(x);


}
}