9月30日记录

完成了一个能够列出30道四则运算的java程序，
题目要求：乘法不超过四位数，减法大于零，除法结果为整数；
实现可视化界面，并且能够计算得分与计时；

点击查看代码

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;

public class MathQuiz2 extends JFrame {
    private static final int NUM_QUESTIONS = 30;
    private static final int TIME_LIMIT = 60; // 60 seconds
    private JTextArea questionArea;
    private JTextField answerField;
    private JButton submitButton;
    private JLabel timerLabel;
    private int currentQuestionIndex = 0;
    private int score = 0;
    private Question[] questions;
    private Timer timer;

    public MathQuiz2() {
        setTitle("Math Quiz");
        setSize(400, 300);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLayout(new BorderLayout());

        questionArea = new JTextArea();
        questionArea.setEditable(false);
        questionArea.setLineWrap(true);
        questionArea.setWrapStyleWord(true);
        add(new JScrollPane(questionArea), BorderLayout.CENTER);

        JPanel inputPanel = new JPanel();
        answerField = new JTextField(10);
        submitButton = new JButton("提交答案");
        timerLabel = new JLabel("剩余时间: " + TIME_LIMIT);
        inputPanel.add(answerField);
        inputPanel.add(submitButton);
        inputPanel.add(timerLabel);
        add(inputPanel, BorderLayout.SOUTH);

        submitButton.addActionListener(new SubmitAnswerListener());

        generateQuestions();
        displayNextQuestion();
        startTimer();

        setVisible(true);
    }

    private void generateQuestions() {
        questions = new Question[NUM_QUESTIONS];
        Random random = new Random();

        for (int i = 0; i < NUM_QUESTIONS; i++) {
            int a = random.nextInt(100); // 0-99
            int b = random.nextInt(100); // 0-99
            int operation = random.nextInt(4); // 0:加, 1:减, 2:乘, 3:除

            switch (operation) {
                case 0: // 加法
                    questions[i] = new Question(a + " + " + b, a + b);
                    break;
                case 1: // 减法
                    if (a >= b) {
                        questions[i] = new Question(a + " - " + b, a - b);
                    } else {
                        i--; // 重新生成题目
                    }
                    break;
                case 2: // 乘法
                    int c = random.nextInt(100); // 0-99
                    if (a * b <= 9999) {
                        questions[i] = new Question(a + " * " + b, a * b);
                    } else {
                        i--; // 重新生成题目
                    }
                    break;
                case 3: // 除法
                    if (b != 0 && a % b == 0) {
                        questions[i] = new Question(a + " / " + b, a / b);
                    } else {
                        i--; // 重新生成题目
                    }
                    break;
            }
        }
    }

    private void displayNextQuestion() {
        if (currentQuestionIndex < NUM_QUESTIONS) {
            questionArea.setText(questions[currentQuestionIndex].getQuestion());
            answerField.setText("");
            answerField.requestFocus();
        } else {
            endQuiz();
        }
    }

    private void startTimer() {
        timer = new Timer(1000, new ActionListener() {
            private int timeLeft = TIME_LIMIT;

            @Override
            public void actionPerformed(ActionEvent e) {
                if (timeLeft > 0) {
                    timeLeft--;
                    timerLabel.setText("剩余时间: " + timeLeft);
                } else {
                    ((Timer) e.getSource()).stop();
                    endQuiz();
                }
            }
        });
        timer.start();
    }

    private void endQuiz() {
        timer.stop();
        JOptionPane.showMessageDialog(this, "测验结束！您的得分是: " + score + "/" + NUM_QUESTIONS);
        System.exit(0);
    }

    private class SubmitAnswerListener implements ActionListener {
        @Override
        public void actionPerformed(ActionEvent e) {
            try {
                int answer = Integer.parseInt(answerField.getText());
                if (answer == questions[currentQuestionIndex].getAnswer()) {
                    score++;
                }
                currentQuestionIndex++;
                displayNextQuestion();
            } catch (NumberFormatException ex) {
                JOptionPane.showMessageDialog(MathQuiz2.this, "请输入有效的数字！");
            }
        }
    }

    private static class Question {
        private final String question;
        private final int answer;

        public Question(String question, int answer) {
            this.question = question;
            this.answer = answer;
        }

        public String getQuestion() {
            return question;
        }

        public int getAnswer() {
            return answer;
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(MathQuiz2::new);
    }
}

界面显示：