西安莲湖区学区:哪位高手能解决一下这个简单的JAVA程序,让它能用行 高分悬赏

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
public class averagescore extends Applet implements ActionListener
{ TextField TF1,TF2;
Label L1,L2,L3;
String answerstr;
double d1=0,d2;
int n=5;

public void actionperformed(ActionEvent evt)
{
L1=new Label("请输入班的人数:");
add(L1);
TF1=new TextField(6);
add(TF1);
L2=new Label("请输入第1个学生的成绩是:");
add(L2);
TF2=new TextField(6);
add(TF2);
L3=new Label("这个班的学生的平均成绩是:");
TF1.addActionListener(this);
try
{
d2=result();
L3.setText("平均成绩是:"+d2);}
catch(NumberFormatException e)
{
L3.setText(e.getMessage());
}
catch(NumberRangeException ee)
{
answerstr="输入的只能是0-100的数字";
L3.setText(answerstr);
}
repaint();
}
public double result()throws NumberRangeException
{
double answer=0;
try
{
//n:=int.valueOf(TF1.getText()).intValue();
for(int i=0;i<n;i++)
{
TF2.addActionListener(this);
d2=double.valueOf(TF2.getText()).doubleValue();
if (d2>100||d2<0)
{
NumberRangeException ee=new NumberRangeException("输入数字不在范围内,请重输入");
throw ee;
}
d1+=double.valueOf(TF2.getText()).doubleValue();
answer=d1/n;
}
}
catch(ArithmeticException eee)
{answerstr=eee.tostring();}
return answer;
}
}
class NumberRangeException extends Exception
{
NumberRangeException(String msg)
{super(msg);
}
}