I don't know how to write code to exit for this program.someone please help me :(
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Panel extends JPanel implements ActionListener{
private JTextField height, weight, answer;
private JButton calc, clear, exit;
public Panel(){
this.setLayout(new GridLayout(2,1));
JPanel topPanel = new JPanel();
topPanel.add(new JLabel("WEIGHT(KG)"));
topPanel.add(height = new JTextField(5));
topPanel.add(new JLabel("HEIGHT(M)"));
topPanel.add(weight = new JTextField(5));
topPanel.add(new JLabel("BMI"));
topPanel.add(answer =new JTextField(10));
JPanel bottomPanel = new JPanel();
bottomPanel.add(calc = new JButton("CALCULATE"));
bottomPanel.add(clear = new JButton("CLEAR"));
bottomPanel.add(exit = new JButton("EXIT"));
this.add(topPanel);
this.add(bottomPanel);
calc.addActionListener(this);
clear.addActionListener(this);
exit.addActionListener(this);
answer.setEditable(false);
}
public void actionPerformed(ActionEvent e)
{
double w =Double.parseDouble(weight.getText());
double h =Double.parseDouble(height.getText());
double ans=0;
if(e.getSource()==calc)
{
ans = (w/(h*h));
}
else if(e.getSource()==clear)
{
height.setText("");
weight.setText("");
}
else if(e.getSource()==exit) ////what i must write to make program exit?
{
}
answer.setText(""+ans);
if(ans>0&&ans<18.5)
{
answer.setBackground(Color.YELLOW);
}
else if(ans>18.5&&ans<25.0)
{
answer.setBackground(Color.GREEN);
}
else if(ans>=25.0)
{
answer.setBackground(Color.RED);
}
}
}