简易小学生四则运算练习软件（自动出题判题）-java实现

一、主要功能说明

1. 输入用户名后可以点击开始做题按钮，出题时每次出十题，提交后会显示答案。可以选择重做或再次开始做题（不同的题）
2. 输入用户名后可以点击查看记录按钮，查看自己历次做题记录。
3. 可以选择每次出题的运算类型和位数。运算类型可选+、-、*、/或混合，位数可选1、2、3、4位。默认运算类型为+，运算位数为0。
4. 除数不能为0，减法结果不为负。
5. 每次做题时会有倒计时显示，需要在120s内做完，如果时间到了还没提交则会自动提交。其实原本设计的时候应该是可以自己规定最大时间的，但是写的时候并没有实现这个功能。

二、运行截图

1. 刚刚运行之后的界面：
   

2. 出题
   

3. 提交后
   

4. 重做并再次提交后（这次有部分答案是错的）
   

5. 查看记录
   

三、类的设计（各类之间的关系）

1. Operation类
   重要属性：两个操作数、正确答案、用户答案
   重要方法：抽象方法operation，用于对操作数的运算。答案的输出、用户答案的set、答案是否正确的比对。
2. +、-、*、/类继承于Operation类，重写operation方法。减法和除法还要保证除数不能为0等。
3. MyExGUI类
   界面的布局、按钮事件的监听、倒计时的实现等等。
4. ArithmeticTest8类，调用MyExGUI。（不知道把所有东西都写在MyExGUI是不是正确的做法）

另：关于Operation 类中isNumRight();setRange();之类方法的作用。在写倒计时之前实现过另一个功能，就是计算比如说一位数的加法，一定不对小于0，也不会大于18，如果出现了可能范围内的数据就会进行提醒（自定义异常NumberTooBigException），用户无法进行提交。但是后来由于加了倒计时，在倒计时结束时无论用户输了什么都还是要提交的就把这个功能删去了。但是有些函数还是没有删去。

四、源代码

1. MyExGUI.java

package visibleArithmeticExercise;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import visibleArithmeticExercise.Operation;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;

public class MyExGUI {

    private JFrame mainWindow = new JFrame("四则运算练习软件");

    //面板
    private JPanel selectPanel = new JPanel();
    private JPanel mainPanel = new JPanel();
    private JPanel commandP = new JPanel();

    private JButton JBRedo = new JButton("重做");
    private JButton JBStart = new JButton("开始做题");

    private JLabel JLUsersName = new JLabel("请输入你的用户名：");
    private JLabel JLChooseOp = new JLabel("请选择运算类型：");
    private JLabel JLNumberDigit = new JLabel("请选择运算位数：");
    private JLabel JLBAnsTip = new JLabel("输入答案");
    private JLabel JLBRemainTip = new JLabel("余数");

    private JTextField JTFUserName = new JTextField(8);//10的单位不是px 而是指定列数
    private String[] operationType = {"+","-","*","/","混合"};
    private String[] numberOfDigitType = {"1","2","3","4"};
    private JComboBox<String> JCBOperationSelect = new JComboBox<String>(operationType);//JComboBox 泛型 需要加上<E>
    private JComboBox<String> JCBNumberOfDigit = new JComboBox<String>(numberOfDigitType);

    //显示题目的JLabel
    private JLabel[] JLBQuestions= new JLabel[10];
    //显示正确答案的JLabel
    private JLabel[] JLBAnswers = new JLabel[10];
    //显示用户答案是否正确的JLabel
    private JLabel[] JLBIsTrue = new JLabel[10];

    private JTextField[] JTFUsersAnswer = new JTextField[10];//定义变量时需要赋初值，不然会出现空指针异常问题
    private JTextField[] JTFRemainder = new JTextField[10];

    //设置Font
    private Font buttonFont = new Font("微软雅黑",Font.PLAIN,16);
    private Font JLBFont = new Font("微软雅黑",Font.BOLD,18);
    private Font JTFFont = new Font("微软雅黑",Font.PLAIN,18);
    private Font JLBAnsFont = new Font("微软雅黑",Font.PLAIN,16);

    //类型为Operation的questions数组，只有这个才和Operation类等等那些类关联起来
    private Operation[] questions = new Operation[10];
    //用户答案数组
    private int[] userAnswer = new int[10];
    //用户余数数组
    private int[] remainder = new int[10];

    private int scores ,n = 1;
    private JLabel JLBScores = new JLabel("你的成绩为:");
    private JButton JBOpenFile = new JButton("查看记录");
    private String chara = "+";
    private File pFile = new File("四则运算记录");

    private int usedTime;
    boolean runFlag = false;//runFlag默认为false
    private JPanel PTime = new JPanel();
    private JLabel JLBRemainTime = new JLabel("剩余时间：");
    private JTextField JTFWtime = new JTextField("120");
    private JLabel JLBTime = new JLabel("用时：");
    //LimitTime t = new LimitTime();//线程不可以在这里new

    //倒计时线程
    class LimitTime extends Thread{
        public void run()
        {
            runFlag = true;
            int i = 120;
            usedTime = 0;
            while(runFlag && i >= 0)
            {
                JTFWtime.setText(""+i);
                try {
                    sleep(1000);
                    usedTime++;
                } catch (InterruptedException e) {
                    JFrame jf = new JFrame();
                    JOptionPane.showMessageDialog(jf,"出现了未知问题，请重启程序");
                }
                i--;
            }
            //runFlag = false;
            for(int j = 0;j < 10;j++)
            {
                if(JTFUsersAnswer[j].getText().equals(""))
                {
                    JTFUsersAnswer[j].setText("0");
                }
            }
            printAnswer();//倒计时结束，则调用printAnswer()方法
            JBStart.setText("开始做题");
            JLBTime.setText("用时："+usedTime);
        }
    }

    public MyExGUI(){

        //布局用户名&选择面板
        selectPanel.setPreferredSize(new Dimension(700,50));
        //selectPanel.setLayout(new GridLayout(1,6,25,20));
        JLUsersName.setFont(JLBFont);
        selectPanel.add(JLUsersName);
        JTFUserName.setFont(JLBFont);
        selectPanel.add(JTFUserName);
        JLChooseOp.setFont(JLBFont);
        selectPanel.add(JLChooseOp);
        JCBOperationSelect.setPreferredSize(new Dimension(50,25));       //当selectPanel.setLayout那句存在时，这里的设置无效
        selectPanel.add(JCBOperationSelect);
        JLNumberDigit.setFont(JLBFont);
        selectPanel.add(JLNumberDigit);
        JCBNumberOfDigit.setPreferredSize(new Dimension(50,25));
        selectPanel.add(JCBNumberOfDigit);

        //布局主面板
        mainPanel.setPreferredSize(new Dimension(700,400));
        //mainPanel.setLayout(new GridLayout(10,3,5,10));
        GridBagLayout gridbag = new GridBagLayout();
        GridBagConstraints GBC = new GridBagConstraints();
        GBC.weightx = 1;//加上这两行之后文本框的大小会和不加时不同 因为它描述的是随面板变化的情况 而现在面板的设定值是800*500 因此不同(不以设定大小为默认值)
        GBC.weighty = 1;
        //GBC.fill = GridBagConstraints.BOTH;//weightx描述的是网格的大小随面板大小变化，组件的大小并不会随之变化 要使组件随之变化需要控制它对所在位置的填充方式
        //GBC.insets = new Insets(1,1,2,2);
        GBC.gridx = 1;
        GBC.gridy = 0;
        GBC.anchor = GridBagConstraints.WEST;
        gridbag.setConstraints(JLBAnsTip, GBC);
        JLBAnsTip.setFont(JLBFont);
        mainPanel.add(JLBAnsTip);

        GBC.gridx = 2;
        gridbag.setConstraints(JLBRemainTip, GBC);
        JLBRemainTip.setFont(JLBFont);
        mainPanel.add(JLBRemainTip);

        GBC.gridx = 4;
        GBC.gridwidth = 2;
        GBC.anchor = GridBagConstraints.CENTER;
        gridbag.setConstraints(JLBScores, GBC);
        JLBScores.setFont(JLBFont);
        mainPanel.add(JLBScores);

        for(int i = 0;i < 5;i++)
        {
            JLBQuestions[i] = new JLabel("点击开始做题显示题目");
            JLBQuestions[i].setFont(JLBFont);
            JTFUsersAnswer[i] = new JTextField(5);                      //一定要加这行 不然会出现空指针错误
            JTFUsersAnswer[i].setFont(JTFFont);
            JTFRemainder[i] = new JTextField(3);
            JTFRemainder[i].setFont(JTFFont);
            JLBAnswers[i] = new JLabel("");
            JLBAnswers[i].setFont(JLBAnsFont);
            JLBIsTrue[i] = new JLabel("");
            JLBIsTrue[i].setFont(JLBAnsFont);

            //gridbag.setConstraints(JLBQuestions[i],new GridBagConstraints(i,0,5,10,1,1,GridBagConstraints.CENTER,GridBagConstraints.NONE,new Insets(2,2,2,2),0,0));
            //gridbag.setConstraints(JTFUsersAnswer[i],new GridBagConstraints(i,1,5,10,1,1,GridBagConstraints.CENTER,GridBagConstraints.NONE,new Insets(2,2,2,2),0,0));
            //gridbag.setConstraints(JTFRemainder[i],new GridBagConstraints(i,2,5,10,1,1,GridBagConstraints.CENTER,GridBagConstraints.NONE,new Insets(2,2,2,2),0,0));
            GBC.gridwidth = 1;
            GBC.gridx = 0;
            GBC.gridy = 2*i+1;
            GBC.anchor = GridBagConstraints.EAST;
            gridbag.setConstraints(JLBQuestions[i], GBC);
            mainPanel.add(JLBQuestions[i]);
            GBC.anchor = GridBagConstraints.CENTER;
            GBC.gridy = 2*i+2;
            GBC.gridwidth = 2;
            gridbag.setConstraints(JLBAnswers[i], GBC);
            mainPanel.add(JLBAnswers[i]);

            GBC.gridwidth = 1;
            GBC.gridx = 1;
            GBC.gridy = 2*i+1;
            GBC.anchor = GridBagConstraints.WEST;
            gridbag.setConstraints(JTFUsersAnswer[i],GBC);
            mainPanel.add(JTFUsersAnswer[i]);

            GBC.gridx = 2;
            gridbag.setConstraints(JTFRemainder[i],GBC);
            mainPanel.add(JTFRemainder[i]);
            GBC.gridy = 2*i+2;
            gridbag.setConstraints(JLBIsTrue[i], GBC);
            mainPanel.add(JLBIsTrue[i]);
        }

        for(int i = 5;i < 10;i++)
        {
            JLBQuestions[i] = new JLabel("点击开始做题显示题目");
            JLBQuestions[i].setFont(JLBFont);
            JTFUsersAnswer[i] = new JTextField(5);                      //一定要加这行 不然会出现空指针错误
            JTFUsersAnswer[i].setFont(JTFFont);
            JTFRemainder[i] = new JTextField(3);
            JTFRemainder[i].setFont(JTFFont);
            JLBAnswers[i] = new JLabel("");
            JLBAnswers[i].setFont(JLBAnsFont);
            JLBIsTrue[i] = new JLabel("");
            JLBIsTrue[i].setFont(JLBAnsFont);

            GBC.gridx = 4;
            GBC.gridy = 2*i-9;
            GBC.anchor = GridBagConstraints.EAST;
            gridbag.setConstraints(JLBQuestions[i], GBC);
            mainPanel.add(JLBQuestions[i]);
            GBC.anchor = GridBagConstraints.CENTER;
            GBC.gridy = 2*i-8;
            GBC.gridwidth = 2;
            gridbag.setConstraints(JLBAnswers[i], GBC);
            mainPanel.add(JLBAnswers[i]);

            GBC.gridwidth = 1;
            GBC.gridx = 5;
            GBC.gridy = 2*i-9;
            GBC.anchor = GridBagConstraints.WEST;
            gridbag.setConstraints(JTFUsersAnswer[i],GBC);
            mainPanel.add(JTFUsersAnswer[i]);

            GBC.gridx = 6;
            gridbag.setConstraints(JTFRemainder[i],GBC);
            mainPanel.add(JTFRemainder[i]);
            GBC.gridy = 2*i-8;
            gridbag.setConstraints(JLBIsTrue[i], GBC);
            mainPanel.add(JLBIsTrue[i]);

        }
        mainPanel.setLayout(gridbag);

        //布局命令面板
        commandP.setLayout(new FlowLayout(FlowLayout.CENTER,60,20)); 
        JLBRemainTime.setFont(JLBFont);
        JLBTime.setFont(JLBFont);
        JTFWtime.setFont(JTFFont);
        PTime.setLayout(new FlowLayout(FlowLayout.LEFT,10,20));
        PTime.add(JLBRemainTime);
        PTime.add(JTFWtime);
        PTime.add(JLBTime);
        commandP.add(PTime);
        JBStart.setFont(buttonFont);
        commandP.add(JBStart);
        JBRedo.setFont(buttonFont);
        commandP.add(JBRedo);
        JBOpenFile.setFont(buttonFont);
        commandP.add(JBOpenFile);

        //使用匿名嵌套类的方式注册开始按钮的事件处理监听器对象
        JBStart.addActionListener(
                new ActionListener() {
                    @Override
                    public void actionPerformed(ActionEvent e) {
                        if(JBStart.getText().equals("开始做题"))
                        {
                            if(JTFUserName.getText().trim().equals(""))
                            {
                                JFrame nullNameWarning = new JFrame();
                                JOptionPane.showMessageDialog(nullNameWarning,"请输入用户名");//确保用户输入用户名
                            }
                            else{
                                start(); //如果按钮上面的文字是"开始做题"，则调用start()方法出题
                                JBStart.setText("提交答案"); 
                                //倒计时线程开始
                                LimitTime t = new LimitTime();
                                t.start();
                            } 
                        }
                        else
                        {
                            for(int i = 0;i < 10;i++)
                            {
                                if(JTFUsersAnswer[i].getText().equals(""))
                                {
                                    JTFUsersAnswer[i].setText("0");
                                }
                            }
                            runFlag = false;//将runFlag设置为false（线程就会不再执行while循环里的内容）
                            //printAnswer();//这里不用再调用printWriter方法了，因为线程那边结束的时候会对它进行调用。
                            JLBTime.setText("用时："+usedTime);
                            JBStart.setText("开始做题");

                            /*int flag = 1;//是否完成每道题
                            for(int i = 0;i < 10;i++)
                            {
                                if(JTFUsersAnswer[i].getText().equals(""))
                                {
                                    JFrame nullAns = new JFrame();
                                    JOptionPane.showMessageDialog(nullAns,"请确保已完成每道题");
                                    flag = 0;//有题目没完成
                                    break;
                                }
                            }
                            if(flag == 1)
                            {
                                printAnswer();//如果按钮上面的文字是"提交答案"，则调用printAnswer()方法
                                JBStart.setText("开始做题");
                            }*/
                            //使用计时器的话不需要完成每道题

                        }
                    }
                }
        );

        //监听重做按钮
        JBRedo.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                if(JBStart.getText().equals("开始做题"))//若已提交答案 则可以进行重做
                {
                    for(int i = 0;i < 10;i++)
                    {
                        JTFUsersAnswer[i].setText("");
                        JTFRemainder[i].setText("");
                        JLBAnswers[i].setText("");
                        JLBIsTrue[i].setText("");
                        JLBScores.setText("");
                    }
                    JLBTime.setText("用时：");
                    LimitTime t = new LimitTime();
                    t.start();
                    JBStart.setText("提交答案"); 
                }
                else//答案未提交 不能重做
                {
                    JFrame notSubmit = new JFrame();
                    JOptionPane.showMessageDialog(notSubmit,"提交后才可以重做！提交前可以直接更改答案！");
                }
            }
        });

        //查看以往做题记录的按钮监听器
        JBOpenFile.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){

                if(JTFUserName.getText().trim().equals(""))
                {
                    JFrame nullNameWarning = new JFrame();
                    JOptionPane.showMessageDialog(nullNameWarning,"请输入用户名");//确保用户输入用户名
                }
                else{
                    //一般不能实例化一个Runtime对象，应用程序也不能创建自己的Runtime 类实例，但可以通过getRuntime 方法获取当前Runtime运行时对象的引用。一旦得到了一个当前的Runtime对象的引用，就可以调用Runtime对象的方法去控制Java虚拟机的状态和行为。
                     Runtime ce=Runtime.getRuntime();
                     pFile.mkdirs();
                     String filename = JTFUserName.getText()+".his";
                     File aUserRec = new File(pFile,filename);
                     if(aUserRec.exists())
                     {
                         try{
                            //ce.exec("cmd   /c   start  "+aUserRec.getAbsolutePath());//这样是不能打开的 因为没有东西能打开.his文件 会跳出来搜索应用商店
                         ce.exec("notepad.exe "+aUserRec.getAbsolutePath());
                         }catch(IOException exc){
                             exc.printStackTrace();
                         }
                     }else{
                     JFrame nullFileWarning = new JFrame();
                     JOptionPane.showMessageDialog(nullFileWarning,"该用户暂无记录!");
                     }
                }   
            }
        });

        //尽量把主窗体的设置都放到最后
        mainWindow.add(selectPanel,BorderLayout.NORTH);
        mainWindow.add(mainPanel,BorderLayout.CENTER);
        mainWindow.add(commandP, BorderLayout.SOUTH);
        mainWindow.pack();
        mainWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        mainWindow.setSize(800,500);//设置窗体大小
        mainWindow.setLocationRelativeTo(null);//将窗口置于屏幕中间
        mainWindow.setVisible(true);//设置为可见 要放在最后 放在前面则只能看见用户名和选择面板 主面板等需要拖动窗口大小才能看见
    }

    public void start(){
        //清除TextField和答案标签的内容
        for(int i = 0;i < 10;i++)
        {
            JTFUsersAnswer[i].setText("");
            JTFRemainder[i].setText("");
            JLBAnswers[i].setText("");
            JLBIsTrue[i].setText("");
            JLBScores.setText("");
            JLBTime.setText("用时：");
        }

        //获取ComboBox的选中值
        chara = (String) JCBOperationSelect.getSelectedItem();
        n = Integer.valueOf((String)JCBNumberOfDigit.getSelectedItem());

         //根据选择的运算出题
        int flag = 0;
        if(chara.equals("混合"))
            flag = 1;
        for(int i = 0;i < 10;i++)
        {
            if(flag == 1)
            {
                int tempCh = (int)(Math.random()*4+1);
                switch(tempCh)
                {
                case 1:
                    chara = "+";
                    break;
                case 2:
                    chara = "-";
                    break;
                case 3:
                    chara = "*";
                    break;
                case 4:
                    chara = "/";
                    break;
                }
            }

            switch(chara)
            {
             case "+":
                 questions[i] = new Addition(n);
                 JLBQuestions[i].setText(questions[i].printQuestion());
                 break;
             case "-":
                 questions[i] = new Subtraction(n);
                 JLBQuestions[i].setText(questions[i].printQuestion());
                 break;
             case "*":
                 questions[i] = new Multiplication(n);
                 JLBQuestions[i].setText(questions[i].printQuestion());
                 break;
             case "/":
                 questions[i] = new Division(n);
                 JLBQuestions[i].setText(questions[i].printQuestion());
                 break;
             default:
                    JFrame jf = new JFrame();
                    JOptionPane.showMessageDialog(jf,"出现未知错误，请重启程序。");
            }
        }
    }

    //在面板上显示每题的正确答案、得分和用时，并且将每次做题的记录写入文件
    public void printAnswer()
    {
        //成绩初始值为100
        scores = 100;

        //对于每道题
        for(int i = 0; i < 10;i++)
        {
            //给用户的答案这一数组赋值（getText的结果为String）
            userAnswer[i] = Integer.valueOf(JTFUsersAnswer[i].getText());

            //如果没有填余数，则默认用户认为余数为0，并给余数数组赋值
            if(JTFRemainder[i].getText().equals(""))
            {
                remainder[i] = 0;
            }

            //否则用用户填的余数给余数数组赋值
            else
            {
                remainder[i] = Integer.valueOf(JTFRemainder[i].getText());
            }


            //questions的类型是operation，用答案和余数这两个数组给questions这个数组赋值
            questions[i].setUsersAnswer(userAnswer[i],remainder[i]);

            //以下这种分开是否有余数的做法是错误的，因为在运算为混合时chara的值是看第十题的（第十题的chara会覆盖掉前面的）。 万一除法没有余数就会报错
            /*if(chara.equals("/"))
            {

                remainder[i] = Integer.valueOf(JTFRemainder[i].getText());
                questions[i].setUsersAnswer(userAnswer[i],remainder[i]);
            }
            else
            {
                questions[i].setUsersAnswer(userAnswer[i]);
            }*/

            //使正确答案显示在面板上
            JLBAnswers[i].setText(questions[i].ptintQA());

            //在面板上显示答案是否正确
            JLBIsTrue[i].setText(questions[i].isCorrect());

            //如果错误则将答案和是否正确两个标签的字体颜色设置为红色
            if(JLBIsTrue[i].getText().equals("回答错误"))
            {
                JLBAnswers[i].setForeground(Color.RED);
                JLBIsTrue[i].setForeground(Color.RED);
                scores-=10;
            }
            //正确为黑色
            else
            {
                JLBAnswers[i].setForeground(Color.BLACK);
                JLBIsTrue[i].setForeground(Color.BLACK);
            }
        }
        //显示成绩
        JLBScores.setText("你的成绩为："+ scores);

        //创建用户文件
        pFile.mkdirs();
        String filename = JTFUserName.getText()+".his";
        File aUserRec = new File(pFile,filename);
        if(! (aUserRec.exists()))
        {
            try{
                aUserRec.createNewFile();
            }catch(Exception e){
                e.printStackTrace();
                JFrame jf = new JFrame();
                JOptionPane.showMessageDialog(jf,"用户文件创建失败");
            }   
        }

        //将每道题的正确答案和用户答案写入文件
        for(int i = 0;i < 10;i++)
        {
            questions[i].writeToFile(aUserRec);
        }

        //将得分和用时写入文件
        try
        {
            PrintWriter out = new PrintWriter(new FileWriter(aUserRec,true));
            out.println("");
            out.println("你此次的得分是："+scores+"    "+"所用时间为："+usedTime+"秒");
            out.println("");
            out.println("");
            out.close();
        }catch(FileNotFoundException e){
            System.err.println("File not found!" );
        }catch(IOException e2){
            e2.printStackTrace();
        }       
    }   
}

2.Operation.java

package visibleArithmeticExercise;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;

public abstract class Operation {
    protected int op1,op2,remainder,usersRemainder,n,correctAnswer,usersAnswer,maxInt=1;
    protected String ch;
    protected long minRange,maxRange;

    public Operation(String ch,int n) {
        super();
        this.ch = ch;
        this.n = n;
    }

    public abstract void operation();
    public abstract void isNumRight();
    public abstract void setRange();

    protected void getRanNum()
    {
        op1 = (int)(Math.random()*Math.pow(10,n));
        op2 = (int)(Math.random()*Math.pow(10,n));
    }

    public void setUsersAnswer(int usersAnswer,int usersRemainder) //throws Exception
    {
        /*setRange();
        if(usersAnswer < minRange || usersAnswer > maxRange)
            throw new NumberTooBigException("答案范围应为"+minRange+"到"+maxRange);*/
        this.usersAnswer = usersAnswer;
        this.usersRemainder = usersRemainder;
    }

    public void setUsersAnswer(int usersAnswer) //throws Exception
    {
        setUsersAnswer(usersAnswer,0);
    }

    public String isCorrect()
    {
        if(usersAnswer == correctAnswer)
            return "回答正确";
        else
            return "回答错误";
    }

    public String printQuestion()
    {
        getRanNum();
        isNumRight();
        return op1+" "+ch+" "+op2+" =";
    }

    public String ptintQA()
    {
        operation();
        return "答案："+op1+" "+ch+" "+op2+" = "+correctAnswer;
    }

    public void writeToFile(File aFile)
    {
        try
        {
            PrintWriter out = new PrintWriter(new FileWriter(aFile,true));
            out.println("题目："+op1+" "+ch+" "+op2);
            out.println("你的答案："+usersAnswer + "    "+ "正确答案："+correctAnswer);
            out.close();
        }catch(FileNotFoundException e){
            System.err.println("File not found!" );
        }catch(IOException e2){
            e2.printStackTrace();
        }       
    }
}

3.Addition.java

package visibleArithmeticExercise;

import visibleArithmeticExercise.Operation;

public class Addition extends Operation {

    static String ch = "+";

    public Addition(int n) {
        super(ch,n);
    }

    @Override
    public void operation() {
        correctAnswer = op1 + op2;
    }

    public void isNumRight(){}

    public void setRange(){
        minRange = 0;
        maxRange = maxInt + maxInt;
    }
}

4.Subtraction.java

package visibleArithmeticExercise;

import visibleArithmeticExercise.Operation;

public class Subtraction extends Operation{

    static String ch = "-";

    public Subtraction(int n) {
        super(ch,n);
    }

    public void operation() {
        correctAnswer = op1 - op2;
    }

    public void isNumRight(){
        while(op1 == op2)
            getRanNum();
        if(op1 < op2)
        {
            int temp = op1;
            op1 = op2;
            op2 = temp;
        }
    }

    public void setRange(){
        minRange = -maxInt;
        maxRange = maxInt;
    }
}

5.Multiplication.java

package visibleArithmeticExercise;

import visibleArithmeticExercise.Operation;

public class Multiplication extends Operation {

    static String ch = "X";

    public Multiplication(int n) {
        super(ch,n);
    }

    @Override
    public void operation() {
        correctAnswer = op1 * op2;
    }

    @Override
    public void isNumRight() {}

    public void setRange(){
        minRange = 0;
        maxRange = maxInt * maxInt;
    }

}

6.Division.java

package visibleArithmeticExercise;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;

import visibleArithmeticExercise.Operation;

public class Division extends Operation {

    static String ch = "/";

    public Division(int n) {
        super(ch,n);
    }

    @Override
    public void operation() {
        // TODO Auto-generated method stub
        correctAnswer = op1 / op2;
        remainder = op1 % op2;
    }

    public String isCorrect()
    {
        if(usersAnswer == correctAnswer && remainder == usersRemainder)
            return "回答正确";
        else
            return "回答错误";
    }

    public String ptintQA()
    {
        operation();
        return "答案："+op1+" "+ch+" "+op2+" = "+correctAnswer+" "+remainder;
    }

    @Override
    public void isNumRight() {
        while(op2 == 0)
            getRanNum();
    }

    public void setRange(){
        minRange = 0;
        maxRange = maxInt;
    }

    public void writeToFile(File aFile)
    {
        try
        {
            PrintWriter out = new PrintWriter(new FileWriter(aFile,true));
            out.println("题目："+op1+" "+ch+" "+op2);
            out.println("你的答案："+usersAnswer+" "+usersRemainder + "    "+ "正确答案："+correctAnswer+" "+remainder);
            out.close();
        }catch(FileNotFoundException e){
            System.err.println("File not found!" );
        }catch(IOException e2){
            e2.printStackTrace();
        }       
    }
}

7.ArithmeticTest8.java

package visibleArithmeticExercise;

import visibleArithmeticExercise.MyExGUI;

public class ArithmeticTest8 {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        MyExGUI exercise = new MyExGUI();
    }

}