数据结构与算法分析-第一章Java类(04)

定义一个名为GenericCoin的类表示一枚没有面值也没有名字的硬币。这枚硬币应该有一个顶面与一个底面，并且可以标明哪一面朝上。应该能够抛掷这枚硬币使之随机掉落，或者顶面朝上，或者底面朝上。

a.编写一个程序将两枚硬币各抛掷50次。记录并报告每枚硬币各有多少次顶面朝上，报告那一枚硬币顶面朝上的次数多

b.编写一个程序来玩一个简单的抛硬币游戏。要求用户猜测隐蔽会是顶面还是底面朝上，然后跑硬币，并将结果告诉用户，宣告用户的猜测是否正确，并将结果裂成表格。用户可以持续的玩这个游戏，想玩多久就玩多久。当用户退出时，显示一个游戏总结，包括：抛硬币的次数，顶面朝上的次数，底面朝上的次数，猜测正确的次数，和猜测正确的百分比。并可以应用户要求以图形演示每次抛硬币的结果。

GenericCoin类，非常简单，里面有个方法cast表示抛一次硬币动作，用了java里的随机数和取绝对值操作(防止出现负数)，这里用了枚举类表示硬币的正面和反面

package com.crazycoder2010.datastructure.ch01;import java.util.Random;public class GenericCoin {//表示硬币的正面和反面public static enum FACE{FONT,BACK;}private FACE face;public FACE getFace() {return face;}public void cast(){int index = 1;Random random = new Random();index = random.nextInt()%2;this.face = FACE.values()[Math.abs(index)];}}

测试称许a-模拟两个硬币一起抛做数据对比

package com.crazycoder2010.datastructure.ch01;import com.crazycoder2010.datastructure.ch01.GenericCoin.FACE;public class GenericCoinTest {public static void main(String[] args) {GenericCoin coin1 = new GenericCoin();int index1 = countFace(coin1,50);GenericCoin coin2 = new GenericCoin();int index2 = countFace(coin2,50);System.out.println("Coin 1:"+index1);System.out.println("Coin 2:"+index2);}private static int countFace(GenericCoin coin,int times){int total = 0;for(int i = 0;i < times;i++){coin.cast();if(coin.getFace() == FACE.FONT){total++;}}return total;}}

这个称许的输出结果为：

Coin 1:23
Coin 2:21

测试程序b-提供ui界面给用户，这里用的是jframe

package com.crazycoder2010.datastructure.ch01;import java.awt.FlowLayout;import java.awt.HeadlessException;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.event.WindowAdapter;import java.awt.event.WindowEvent;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import javax.swing.JButton;import javax.swing.JComboBox;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JOptionPane;import javax.swing.JScrollPane;import javax.swing.JTable;import javax.swing.table.AbstractTableModel;import com.crazycoder2010.datastructure.ch01.GenericCoin.FACE;public class GenericCoinTestUI extends JFrame {private static int index = 0;private List<Guess> results = new ArrayList<Guess>();// 保存所有猜测结果private Map<FACE, Integer> actual = new HashMap<FACE, Integer>();//实际硬币展示的数量,key:正面/反面，value:对应的硬币正面或反面出现的次数private static final long serialVersionUID = 2948063316297165651L;public GenericCoinTestUI() throws HeadlessException {super();setTitle("抛硬币游戏");setSize(500, 550);setResizable(false);this.getContentPane().setLayout(new FlowLayout());//游戏开始之前反面/正面出现的实际次数都为0actual.put(FACE.FONT, 0);actual.put(FACE.BACK, 0);this.addWindowListener(new WindowAdapter() {@Overridepublic void windowClosing(WindowEvent e) {StringBuffer message = new StringBuffer("----游戏总结----\n");message.append("猜测总次数：").append(results.size()).append("\n");message.append("正面次数：").append(actual.get(FACE.FONT)).append("\n");message.append("反面次数：").append(actual.get(FACE.BACK)).append("\n");int success = doSummarySuccess(results);message.append("猜中次数：").append(success).append("\n");message.append("猜中百分比：").append(Float.valueOf(success)*100/results.size()).append("%\n");JOptionPane.showMessageDialog(null, message);System.exit(0);}});final AbstractTableModel tableModel = new MyTable(this.results);JTable table = new JTable(tableModel);JScrollPane scrollPane = new JScrollPane(table);final JComboBox<String> faces = new JComboBox<String>();faces.addItem("正面");faces.addItem("反面");this.getContentPane().add(faces);JButton throwButton = new JButton("猜猜");this.getContentPane().add(throwButton);final JLabel label = new JLabel();this.getContentPane().add(label);throwButton.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {GenericCoin coin = new GenericCoin();coin.cast();actual.put(coin.getFace(), actual.get(coin.getFace())+1);Guess guess = new Guess(++index, FACE.values()[faces.getSelectedIndex()],coin.getFace() == FACE.values()[faces.getSelectedIndex()]);results.add(guess);label.setText(guess.isRight()?"猜中了！":"没猜中！");tableModel.fireTableDataChanged();}});this.getContentPane().add(scrollPane);}public static void main(String[] args) {new GenericCoinTestUI().setVisible(true);}private int doSummarySuccess(List<Guess> guesses){int total = 0;for(Guess guess : guesses){if(guess.isRight()){total++;}}return total;}private static class MyTable extends AbstractTableModel {private String[] header = { "索引", "猜测", "猜中" };private List<Guess> guesses;private MyTable(List<Guess> guesses){this.guesses = guesses;}@Overridepublic int getRowCount() {return guesses.size();}@Overridepublic String getColumnName(int column) {return header[column];}@Overridepublic int getColumnCount() {return header.length;}@Overridepublic Object getValueAt(int rowIndex, int columnIndex) {Guess guess = guesses.get(rowIndex);if(columnIndex == 0){return guess.getIndex();}else if(columnIndex == 1){return guess.getFace();}else if(columnIndex == 2){return guess.isRight();}return null;}}private static class Guess {//这个类表示用户的一次猜测行为private int index;//猜测的索引，第一次猜猜，第二次猜测。。。private FACE face;//用户猜测的硬币面-正面或反面private boolean right;//这次猜测活动用户是否猜中public Guess(int index, FACE face, boolean right) {this.index = index;this.face = face;this.right = right;}public int getIndex() {return index;}public FACE getFace() {return face;}public boolean isRight() {return right;}}}

看一下运行结果界面：