import java.awt.*;
import java.awt.event.*;

class Labor41 extends Frame{
  String[] feliratok = {"7", "8", "9",
                        "4", "5", "6",
                        "1", "2", "3",
                        "*", "0", "#"};
  Panel buttonPanel;
  TextField numberField;

  class PhoneButton extends Button{
    class PhoneButtonListener implements ActionListener{
      Labor41 caller;
      String number;
      PhoneButtonListener(Labor41 caller, String number){
          this.caller = caller;
          this.number = number;}
      public void actionPerformed(ActionEvent e){
            addNumber(number);}}

    PhoneButton(Labor41 caller, String number){
        super(number);
        this.addActionListener(new PhoneButtonListener(caller, number));}}

  void addNumber(String number){
    numberField.setText(numberField.getText() + number);}

  class MyWindowListener extends WindowAdapter{
    public void windowClosing(WindowEvent e){
        System.exit(0);}}

  Labor41(){
    addWindowListener(new MyWindowListener());
    buttonPanel = new Panel();
    numberField = new TextField();
    setLayout(new BorderLayout());
    buttonPanel.setLayout(new GridLayout(4,3));
    add(numberField,BorderLayout.NORTH);
    for (int i= 0; i < 12; i++){
        buttonPanel.add(new PhoneButton(this, feliratok[i]));}
    add(buttonPanel,BorderLayout.CENTER);
    setSize(300,400);
    setVisible(true);}

  public static void main(String[] args){
    new Labor41();
  }
}