利用传统的递规算法实现汉诺塔的演示程序。
源代码：
/**
*本程序完成的功能是利用汉递规算法实现汉诺塔的动态演示程序
*/
import javax.swing.*;
import java.awt.geom.*;
import java.awt.event.*;
import java.awt.*;
public class Hanio extends JApplet implements ActionListener, Runnable
{
/**
*diskNum是盘子的数量
*/
private int diskNum ;
/**
*各个组件的句柄
*/
private JButton begin, stop;
private JLabel lDiskNum;
private JTextField text;
JPanel pane;
/**
*定义一个线程句柄
*/
private Thread animate;
/**
*定义a,b,c三个柱子上是否有盘子，有哪些盘子
*/
private int adisk[];
private int bdisk[];
private int cdisk[];
public void init()
{
Container content = getContentPane();
content.setLayout(new BorderLayout());
lDiskNum = new JLabel(“盘子的数目”);
text = new JTextField(8);
begin = new JButton(“开始”);
begin.addActionListener(this);
stop = new JButton(“停止”);
stop.addActionListener(this);
pane = new JPanel();
pane.setLayout(new FlowLayout());
pane.add(lDiskNum);
pane.add(text);
pane.add(begin);
pane.add(stop);
content.add(pane, BorderLayout.SOUTH);
}
public void paint(Graphics g)
{
Graphics2D g2D = (Graphics2D)g;
Ellipse2D.Double ellipse;
g2D.setPaint(getBackground());
if(adisk != null)
{
/**
*消除以前画的盘子
*/
for(int j=adisk.length, i=0; –j>=0; i++ )
{
ellipse = new Ellipse2D.Double(20+i*5, 180-i*10, 180-i*10, 20);
g2D.fill(ellipse);
ellipse = new Ellipse2D.Double(220+i*5, 180-i*10, 180-i*10, 20);
g2D.fill(ellipse);
ellipse = new Ellipse2D.Double(420+i*5, 180-i*10, 180-i*10, 20);
g2D.fill(ellipse);
}
drawEllipse(g, 20, adisk);//画A组盘子
drawEllipse(g, 220, bdisk);//画B组盘子
drawEllipse(g, 420, cdisk);//画C组盘子
}
pane.repaint();
}
public void update(Graphics g)
{
paint(g);
}
/**画出椭圆代表盘子，g是图形环境，x是最下面的盘子的横坐标，
*arr是柱子数组
*/
public void drawEllipse(Graphics g,int x,int arr[])
{
Graphics2D g2D = (Graphics2D)g;
Ellipse2D.Double ellipse;
g2D.setPaint(Color.gray);
g2D.draw(new Line2D.Double(x+90, 10, x+90, 180));
for(int j=arr.length, i=0; –j>=0; i++ )
if(arr[j] != 0)
{
if(i%2 == 0)
g2D.setPaint(Color.blue);
else
g2D.setPaint(Color.red);
ellipse = new Ellipse2D.Double(x+i*5, 180-i*10, 180-i*10, 20);
g2D.fill(ellipse);
}
}
public void actionPerformed(ActionEvent e)
{
String command = e.getActionCommand();
if(command.equals(“开始”))
{
/**
*进行初始化，开始的时候只有a柱子上有盘子，其他柱子都没有
*/
diskNum = Integer.parseInt(text.getText());
adisk = new int[diskNum];
for(int i=0; i<adisk.length; i++)
adisk[i] = 1;
bdisk = new int[diskNum];
for(int k=0; k<bdisk.length; k++)
bdisk[k] = 0;
cdisk = new int[diskNum];
for(int i=0; i<cdisk.length; i++)
cdisk[i] = 0;
repaint();
if(animate == null || !animate.isAlive())//创建一个线程
{
animate = new Thread(this);
animate.start();
}
}
if(command.equals(“停止”))
{
for(int k=0; k<bdisk.length; k++)
bdisk[k] = 0;
for(int i=0; i<cdisk.length; i++)
cdisk[i] = 0;
repaint();
text.setText(“”);
animate = null;
}
}
/**
*线程方法，在此调用汉诺塔执行移动盘子操作
*/
public void run()
{
hanio(diskNum, ‘A’, ‘B’, ‘C’);
repaint();
}
/**
*汉诺塔递规调用程序，n是盘子的数量，A，B，C分别代表三个柱子
*/
public void hanio(int n, char A, char B, char C)
{
if(n > 1)
{
hanio(n-1, A, C, B);
pause();//停顿几秒在执行
switch(A)
{
case ‘A’:adisk[n-1] = 0;break;
case ‘B’:bdisk[n-1] = 0;break;
case ‘C’:cdisk[n-1] = 0;break;
default:break;
}
switch(C)
{
case ‘A’:adisk[n-1] = 1;break;
case ‘B’:bdisk[n-1] = 1;break;
case ‘C’:cdisk[n-1] = 1;break;
default:break;
}
repaint();
hanio(n-1, B, A, C);
}
pause();
switch(A)
{
case ‘A’:adisk[n-1] = 0;break;
case ‘B’:bdisk[n-1] = 0;break;
case ‘C’:cdisk[n-1] = 0;break;
default:break;
}
switch(C)
{
case ‘A’:adisk[n-1] = 1;break;
case ‘B’:bdisk[n-1] = 1;break;
case ‘C’:cdisk[n-1] = 1;break;
default:break;
}
repaint();
}
/**
*每隔半妙钟移动一个盘子
*/
public void pause()
{
try{
Thread.sleep(500);//可以修改此值加快盘子移动的速度
}catch(InterruptedException e){}
}
}
