import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class LatihanGUI extends JApplet implements ActionListener {
    private JButton calculate;
    private JLabel radius;
    private JTextField jtfradius;
    private JLabel area;
    private JTextField result;

    @Override
    public void init(){
        Container pane=getContentPane();
        pane.setBackground(Color.pink);
        pane.setLayout(new GridLayout(3,2));
      radius=new JLabel("Radius :");
      pane.add(radius);
      jtfradius=new JTextField(5);
      pane.add(jtfradius);

       area=new JLabel("Area :");
       pane.add(area);
       result=new JTextField();
       pane.add(result);

     calculate=new JButton("calculate");
     pane.add(calculate);


     jtfradius.addActionListener(this);

     calculate.addActionListener(this);

    }

    @Override
    public void actionPerformed(ActionEvent e) {
        double p=Double.parseDouble(jtfradius.getText());

        double pi=3.142;
        double area=Math.PI*(p*p);

        result.setText(""+area);
    }

}