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0
		actual.put(FACE.FONT, 0);
		actual.put(FACE.BACK, 0);
		this.addWindowListener(new WindowAdapter() {
			@Override
			public 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() {
			@Override
			public 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;
		}
		@Override
		public int getRowCount() {
			return guesses.size();
		}
		@Override
		public String getColumnName(int column) {
			return header[column];
		}
		@Override
		public int getColumnCount() {
			return header.length;
		}
		@Override
		public 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：