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 secondsprivate 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); // 0-99int b = random.nextInt(100); // 0-99int 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); // 0-99if (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;@Overridepublic 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 {@Overridepublic 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：