public class ScoreRecord {
    private String studentName;
    private String subject;
    private double score;

    public ScoreRecord(String studentName, String subject, double score) {
        if (studentName == null || studentName.trim().isEmpty()) {
            throw new IllegalArgumentException("姓名不能为空");
        }
        this.studentName = studentName;
        this.subject = subject;
        this.score = score;
    }

    // Getter 和 Setter
    public String getStudentName() { return studentName; }
    public String getSubject() { return subject; }
    public double getScore() { return score; }

    @Override
    public String toString() {
        return "姓名：" + studentName + "，科目：" + subject + "，成绩：" + score;
    }
}

import j*a.util.ArrayList;
import j*a.util.List;

public class ScoreManager {
    private List<ScoreRecord> records;

    public ScoreManager() {
        records = new ArrayList<>();
    }

    public void addRecord(ScoreRecord record) {
        records.add(record);
    }

    public List<ScoreRecord> getAllRecords() {
        return new ArrayList<>(records); // 返回副本避免外部修改
    }

    public double getAverageScore() {
        return records.stream()
                .mapToDouble(ScoreRecord::getScore)
                .*erage()
                .orElse(0.0);
    }
}

import j*ax.swing.*;
import j*a.awt.*;
import j*a.awt.event.ActionEvent;

public class ScoreInputFrame extends JFrame {
    private JTextField nameField = new JTextField(10);
    private JTextField subjectField = new JTextField(10);
    private JTextField scoreField = new JTextField(10);
    private JTextArea outputArea = new JTextArea(10, 30);
    private ScoreManager manager = new ScoreManager();

    public ScoreInputFrame() {
        setTitle("成绩录入系统");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new FlowLayout());

        add(new JLabel("姓名：")); add(nameField);
        add(new JLabel("科目：")); add(subjectField);
        add(new JLabel("分数：")); add(scoreField);

        JButton addButton = new JButton("录入");
        addButton.addActionListener(this::addScore);
        add(addButton);

        outputArea.setEditable(false);
        add(new JScrollPane(outputArea));

        pack();
        setLocationRelativeTo(null);
    }

    private void addScore(ActionEvent e) {
        try {
            String name = nameField.getText().trim();
            String subject = subjectField.getText().trim();
            double score = Double.parseDouble(scoreField.getText().trim());

            ScoreRecord record = new ScoreRecord(name, subject, score);
            manager.addRecord(record);

            outputArea.append(record.toString() + "\n");
            outputArea.append("当前平均分：" + String.format("%.2f", manager.getAverageScore()) + "\n\n");

            // 清空输入框
            nameField.setText("");
            subjectField.setText("");
            scoreField.setText("");

        } catch (NumberFormatException ex) {
            JOptionPane.showMessageDialog(this, "请输入有效的数字分数", "输入错误", JOptionPane.ERROR_MESSAGE);
        } catch (IllegalArgumentException ex) {
            JOptionPane.showMessageDialog(this, ex.getMessage(), "输入错误", JOptionPane.ERROR_MESSAGE);
        }
    }
}

public class Main {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            new ScoreInputFrame().setVisible(true);
        });
    }
}