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

public class Square extends JFrame {

    private class Controller implements ActionListener {
	public void actionPerformed(ActionEvent e) {
	    int value;
	    value= Integer.parseInt(input.getText());
	    input.setText(Integer.toString(value * value));
	}
    }

    private JButton button;
    private JTextField input;

    public Square() {

        super("Square GUI");

	button = new JButton("Square");
	input = new JTextField();
	 
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        setLayout(new GridLayout(1,2));

        add(button);
        add(input);
        button.addActionListener(new Controller());

        pack();
        setVisible(true);
    }

    public static void main(String[] args) {
	Square app;
	app = new Square();
    }
    
}