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

public class MemberVariable implements ActionListener
{
  private JTextField m_tf = new JTextField(10);
  private JLabel m_label = new JLabel();
  private JButton m_button = new JButton("Compute");

  public MemberVariable ()
  {
    JFrame frame = new JFrame("Event Test");
    Container content = frame.getContentPane();
    content.setLayout(new FlowLayout());
    frame.setSize(300,300);
    content.add(m_tf);
    content.add(m_label);
    content.add(m_button);
    m_button.addActionListener(this);
    
    frame.setVisible(true);
  }
  
  public void actionPerformed(ActionEvent ae)
  {
    String text = m_tf.getText();
    int value = 0;
    try
      {
        value = Integer.parseInt(text);
      }
    catch (NumberFormatException nfe)
      {
        return;
      }
    m_label.setText(String.valueOf(value * value));
    
  }


  public static void main(String[] args)
  {
    new MemberVariable();
  }
}