java程序设计教程(第六版)课后习题答案(3)

public PairOfDice()

{

faceValue=1;

faceValue1=2;

}

public int roll()

{

faceValue=(int)(Math.random()*MAX)+1;

return faceValue;

}

public int roll1()

{

faceValue1=(int)(Math.random()*MAX)+1;

return faceValue1;

}

public void setFaceValue(int value)

{

faceValue=value;

}

public int getFaceValue()

{

return faceValue;

}

public void setFaceValue1(int value)

{

faceValue1=value;

}

public int getFaceValue1()

{

return faceValue1;

}

public int Sum()

{

int sum=faceValue+faceValue1;

return sum;

}

public String toString()

{

String result=Integer.toString(faceValue);

return result;

}

}

public class RollingDice2 {

public static void main(String[] args) {

PairOfDice die1=new PairOfDice();

int faceValue=die1.roll();

int faceValue1=die1.roll1();

System.out.println("faceValue="+faceValue+"

faceValue1="+faceValue1);

int sum=die1.Sum();

System.out.println("sum="+sum);

PairOfDice die2=new PairOfDice();

die2.setFaceValue(4);

int faceValue2=die2.getFaceValue();

System.out.println("faceValue2="+faceValue2);

die2.setFaceValue1(3);

int faceValue3=die2.getFaceValue1();

System.out.println("faceValue3="+faceValue3);

int sum2=die2.Sum();

System.out.println("sum2="+sum2);

}

}

App4.13源程序：

//PushDisplayPanel.java

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class PushDisplayPanel extends JPanel {

/**

*

*/

private static final long serialVersionUID = 8617749572451960356L; private int count;

private JButton push;

private JLabel label;

int num;

int I=100;

public PushDisplayPanel()

{

push=new JButton("Push it!");

push.addActionListener(new ButtonListener());

label=new JLabel("Random:"+count);

add (push);

add (label);

setPreferredSize(new Dimension(400,100));

setBackground(Color.pink);

}

private class ButtonListener implements ActionListener {

public void actionPerformed(ActionEvent event)

{

for(int j=0;j<I;j++){

num=(int)(Math.random()*100)+1;

label.setText("Random:"+num);

}

}

}

}

//Random.java

import javax.swing.JFrame;

public class Random {

public static void main(String[] args) {

JFrame frame=new JFrame("Random");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.getContentPane().add(new PushDisplayPanel());

frame.pack();

frame.setVisible(true);

}

}

///////////////////////////////////////////////////////////////////// App4.14源程序：

//AddPanel.java

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class AddPanel extends JPanel {

/**

*

*/

private static final long serialVersionUID = 8617749572451960356L; private int count;

private JButton push,push1;

private JLabel label;

int num=50;

public AddPanel()

{

push=new JButton("Add!");

push1=new JButton("Minus!");

push.addActionListener(new ButtonListener());

push1.addActionListener(new ButtonListener());

label=new JLabel("Number:"+num);

add (push);

add (push1);

add (label);

setPreferredSize(new Dimension(400,100));

setBackground(Color.pink);

}

private class ButtonListener implements ActionListener {

public void actionPerformed(ActionEvent event)

{

if(event.getSource()==push)

num++;

else

num--;

label.setText("Number:"+num);

}

}

}

//Number.java

import javax.swing.JFrame;

public class Number{

/**

* @param args

*/

public static void main(String[] args) {

// TODO 自动生成方法存根

JFrame frame=new JFrame("Random");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.getContentPane().add(new AddPanel());

frame.pack();

frame.setVisible(true);

}

}

///////////////////////////////////////////////////////////// 补充：画一个转动的风车

import java.awt.*;

import java.awt.geom.*;

import javax.swing.*;

public class testarc

{

public static void main(String[] args)

{

FillFrame frame = new FillFrame();

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setVisible(true);

}

}

class FillFrame extends JFrame

{

public FillFrame()

{

setTitle("FillTest");

setSize(400,400);

// add panel to frame

DrawPanel panel = new DrawPanel();

add(panel);

}

}

class DrawPanel extends JPanel implements Runnable

{

private Thread t;

private int k=0;

public DrawPanel(){

setBackground(Color.white);

t = new Thread(this);

t.start();

}

public void paintComponent(Graphics g)

{

super.paintComponent(g);

Graphics2D g2 = (Graphics2D) g;

double xCenter=getWidth()/2;//中心点x

double yCenter=getHeight()/2;//中心点y

double radius=(int)(getWidth()*0.4);//半径

Ellipse2D circle = new Ellipse2D.Double(xCenter-radius,yCenter-radius,2*radius,2*radius); g2.draw(circle);

//画一个风车

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