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

import javax.swing.*;

public class Hanoi {

    public static void main(String[] args) {
        JFrame frame = new JFrame("Hanoi");
        frame.setVisible(false);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JComponent c = new JPanel(new BorderLayout());
        frame.setContentPane(c);
        final JTextArea t = new JTextArea();
        c.setPreferredSize(new Dimension(600,400));
        JScrollPane sp = new JScrollPane(t);         
        c.add(sp, BorderLayout.CENTER);
        final JSlider slider = new JSlider(JSlider.VERTICAL,1,20,4);
        slider.setPaintLabels(true);
        slider.setMajorTickSpacing(1);
        slider.setSnapToTicks(true);
        slider.setMinorTickSpacing(1);
        slider.setPaintTicks(true);
        JButton but = new JButton("Start");
        c.add(slider, BorderLayout.EAST);
        c.add(but, BorderLayout.SOUTH);    
        frame.pack();
        frame.setVisible(true);
        but.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                t.setText("");
                new Thread(new Runnable() {
                    public void run() {
                        hanoi(slider.getValue(),"alpha", "beta", "gamma", t, 1);
                    }                    
                }).start();                                
            }            
        });        
    }


    private static int hanoi(int n, String from, String via, String to, JTextArea t, int c) { 
      if (n > 0) {
        c = hanoi(n-1, from, to, via, t, c);
        t.append(c + ": "+ from + " -> " + to + "\n");
        c++;
        c = hanoi(n-1, via, from, to, t, c);
      }
      return c;
    }

    
}