解释private void CalculatePartialWidth() { int index = -1; List<Result_Line> vLines = ResultLineList.Where(line => line.VLineOrder != null).ToList(); for (int i = 0; i < vLines.Count; i++) { if (vLines[i].VLineOrder == -9999 || vLines[i].VLineOrder == 9999) { continue; } index = ResultLineList.IndexOf(vLines[i]); float width = -1f; if (vLines[i - 1].VLineOrder == -9999) { width = (float)(vLines[i].WidthBetweenVLine + vLines[i + 1].WidthBetweenVLine / 2f); } else if (vLines[i + 1].VLineOrder == 9999) { width = (float)(vLines[i].WidthBetweenVLine / 2f + vLines[i + 1].WidthBetweenVLine); } else { width = (float)((vLines[i].WidthBetweenVLine + vLines[i + 1].WidthBetweenVLine) / 2f); } ResultLineList[index].VLineWidth = NumValid.PrecisionConvert_Width(width); } }

这段代码是一个私有函数，函数名为 CalculatePartialWidth()。函数的主要作用是计算垂线所占部分的宽度，并将计算结果保存到一个列表中。函数中使用了一个名为 ResultLineList 的列表，这个列表中存储了多条直线。函数首先使用 LINQ 查询筛选出 ResultLineList 中的所有垂线，然后遍历这些垂线，计算它们所占部分的宽度，最后将计算结果保存到列表中。具体来说，函数中使用了一个名为 vLines 的列表，这个列表通过 LINQ 查询筛选出了 ResultLineList 中所有垂线。然后，函数通过一个 for 循环遍历 vLines 列表中的每个垂线。如果当前垂线的 VLineOrder 属性为 -9999 或 9999，那么函数将跳过该垂线的计算。否则，函数会通过 IndexOf() 方法计算出当前垂线在 ResultLineList 中的索引值，并将该索引值保存到一个名为 index 的变量中。接下来，函数会根据当前垂线和相邻两个垂线的宽度计算出当前垂线所占部分的宽度，并将计算结果保存到名为 width 的变量中。最后，函数将计算结果通过 PrecisionConvert_Width() 方法转换为指定精度的宽度，并将结果保存到 ResultLineList 中对应垂线的 VLineWidth 属性中。

相关问题

编写一个Java程序，假设文本文件 data.txt 如下： 学号 姓名 性别 省份 出生年月 成绩 -------------------------------------- 1001 小王 男 湖北 1998-11-12 90 1002 小刘 女 北京 1997-01-12 60.5 1003 小张 女 湖南 1997-11-01 86 1004 王艳 男 广东 1998-11-14 55 1005 刘华 女 云南 1998-09-12 76 1006 李华 男 贵州 1998-07-12 92 1007 张艳 女 湖北 1998-10-12 66 从键盘中输入以下格式的字符串 select 字段列表 where 条件 如 select 姓名 性别 省份 出生年月 where 性别=男， 显示所有男同学的姓名，性别，省份，出生年月 select 学号 性别 省份 成绩 where 省份=湖北， 显示所有湖北同学的学号，性别，省份，成绩

好的，您的问题是如何编写一个Java程序，根据指定的格式从文本文件中检索数据并输出查询结果。实际上，您可以采用如下的步骤来实现：

1. 读取输入字符串，解析出要查询的字段列表以及查询条件，存储在相应的变量中。
2. 打开指定的文本文件，并逐行读取数据，对每一行进行解析，存储在一个数据结构中（如List of Map）。
3. 对数据进行过滤，只保留符合查询条件的部分，排除不符合条件的行。
4. 输出查询结果，按照指定的字段列表进行打印。

下面是一份参考代码，仅供您参考：

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;

public class QueryData {

    public static void main(String[] args) {
        // 从键盘读入查询条件
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入查询语句：");
        String query = scanner.nextLine();

        // 解析查询语句
        String[] fields = query.substring(query.indexOf("select") + 7, query.indexOf("where")).trim().split("\\s+");
        String[] conditions = query.substring(query.indexOf("where") + 5).trim().split("\\s+");

        // 读取数据文件并进行查询
        List<Map<String, Object>> data = readDataFile("data.txt");
        List<Map<String, Object>> result = new ArrayList<>();
        for (Map<String, Object> record : data) {
            boolean match = true;
            for (int i = 0; i < conditions.length; i += 3) {
                String key = conditions[i];
                String op = conditions[i + 1];
                String value = conditions[i + 2];
                if (!compare(record.get(key), op, value)) {
                    match = false;
                    break;
                }
            }
            if (match) {
                Map<String, Object> row = new HashMap<>();
                for (String field : fields) {
                    row.put(field, record.get(field));
                }
                result.add(row);
            }
        }

        // 输出查询结果
        for (Map<String, Object> row : result) {
            for (String field : fields) {
                System.out.print(row.get(field) + "\t");
            }
            System.out.println();
        }
    }

    /**
     * 读取数据文件，将每一行解析成一个 Map 返回。
     */
    private static List<Map<String, Object>> readDataFile(String filename) {
        List<Map<String, Object>> data = new ArrayList<>();
        try (BufferedReader reader = new BufferedReader(new FileReader(filename))) {
            String header = reader.readLine();
            String[] keys = header.trim().split("\\s+");
            String line;
            while ((line = reader.readLine()) != null) {
                String[] values = line.trim().split("\\s+");
                if (values.length != keys.length) {
                    System.err.println("数据文件格式错误：" + line);
                    continue;
                }
                Map<String, Object> record = new HashMap<>();
                for (int i = 0; i < keys.length; i++) {
                    record.put(keys[i], values[i]);
                }
                data.add(record);
            }
        } catch (IOException e) {
            System.err.println("读取数据文件出错：" + e.getMessage());
        }
        return data;
    }

    /**
     * 根据操作符比较两个值的大小。
     */
    private static boolean compare(Object left, String op, String right) {
        int cmp = 0;
        if (left instanceof Integer) {
            cmp = ((Integer) left).compareTo(Integer.parseInt(right));
        } else if (left instanceof Double) {
            cmp = ((Double) left).compareTo(Double.parseDouble(right));
        } else if (left instanceof String) {
            cmp = ((String) left).compareTo(right);
        } else {
            System.err.println("不支持的值类型：" + left.getClass().getName());
            return false;
        }
        switch (op) {
            case "=":
                return cmp == 0;
            case "<":
                return cmp < 0;
            case ">":
                return cmp > 0;
            case "<=":
                return cmp <= 0;
            case ">=":
                return cmp >= 0;
            default:
                System.err.println("不支持的操作符：" + op);
                return false;
        }
    }
}

希望这份代码能够帮助您完成您的任务。如果有什么不明白的地方，可以继续提问哦！

use Java to achieve:A GUI-based program is required that will enable people to take a test from a bank of multiple choice questions. Each question consists of: ● the question text; ● 4 possible answers; ● the number of the correct answer (1-4, not 0-3); Questions are held sequentially in a text file with each question held on 6 consecutive lines. An example entry in the questions text file could look like this: What is your favourite colour? Red Green Blue Pink 4 How many Harry Potter books are there? 5 6 7 8 3 The programme should have the following features: ● A menu including Open and Exit where Open starts a JFileChooser to select the file with the questions inside and Exit ends the programme. ● Once a file is loaded, the GUI should display one question and its answers at a time. ● The user should be able to select an answer and they should be informed if they were correct or not. ● The user should be made aware of the number of correctly answered and the total number of questions answered. ● The user should only be able to proceed to the next question once they answered the current one. ● Once all questions have been answered, the user should be informed of their overall score and that the game has finished. The Open menu item should now be enabled to start a new quiz. Optionally, you can add a restart menu item to redo the current quiz.

Sure, I can help you with that. Here is some sample Java code that implements the GUI-based program you described:

import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.ButtonGroup;

public class MultipleChoiceQuiz implements ActionListener {

    private JFrame frame;
    private JFileChooser fileChooser;
    private JButton openButton;
    private JButton exitButton;
    private JButton nextButton;
    private JButton restartButton;
    private JLabel questionLabel;
    private JRadioButton[] answerButtons;
    private ButtonGroup answerGroup;
    private List<Question> questionList;
    private int currentQuestionIndex;
    private int numCorrect;
    private int numAnswered;

    public MultipleChoiceQuiz() {
        frame = new JFrame("Multiple Choice Quiz");
        fileChooser = new JFileChooser();
        openButton = new JButton("Open");
        openButton.addActionListener(this);
        exitButton = new JButton("Exit");
        exitButton.addActionListener(this);
        nextButton = new JButton("Next");
        nextButton.addActionListener(this);
        restartButton = new JButton("Restart");
        restartButton.addActionListener(this);
        questionLabel = new JLabel();
        answerButtons = new JRadioButton[4];
        for (int i = 0; i < answerButtons.length; i++) {
            answerButtons[i] = new JRadioButton();
        }
        answerGroup = new ButtonGroup();
        for (JRadioButton button : answerButtons) {
            answerGroup.add(button);
        }
        questionList = new ArrayList<>();
        currentQuestionIndex = 0;
        numCorrect = 0;
        numAnswered = 0;
        JPanel buttonPanel = new JPanel(new GridLayout(1, 0));
        buttonPanel.add(openButton);
        buttonPanel.add(exitButton);
        JPanel answerPanel = new JPanel(new GridLayout(4, 1));
        for (JRadioButton button : answerButtons) {
            answerPanel.add(button);
        }
        JPanel questionPanel = new JPanel(new BorderLayout());
        questionPanel.add(questionLabel, BorderLayout.NORTH);
        questionPanel.add(answerPanel, BorderLayout.CENTER);
        JPanel controlPanel = new JPanel(new GridLayout(1, 0));
        controlPanel.add(nextButton);
        controlPanel.add(restartButton);
        frame.add(buttonPanel, BorderLayout.NORTH);
        frame.add(questionPanel, BorderLayout.CENTER);
        frame.add(controlPanel, BorderLayout.SOUTH);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        new MultipleChoiceQuiz();
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == openButton) {
            int result = fileChooser.showOpenDialog(frame);
            if (result == JFileChooser.APPROVE_OPTION) {
                File file = fileChooser.getSelectedFile();
                try (BufferedReader reader = new BufferedReader(new FileReader(file))) {
                    questionList.clear();
                    String line;
                    while ((line = reader.readLine()) != null) {
                        String[] parts = line.split(" ");
                        String questionText = parts[0];
                        String[] answers = {parts[1], parts[2], parts[3], parts[4]};
                        int correctAnswer = Integer.parseInt(parts[5]);
                        questionList.add(new Question(questionText, answers, correctAnswer));
                    }
                    currentQuestionIndex = 0;
                    numCorrect = 0;
                    numAnswered = 0;
                    displayCurrentQuestion();
                    nextButton.setEnabled(true);
                    restartButton.setEnabled(false);
                } catch (Exception ex) {
                    JOptionPane.showMessageDialog(frame, "Error reading file: " + ex.getMessage());
                }
            }
        } else if (e.getSource() == exitButton) {
            System.exit(0);
        } else if (e.getSource() == nextButton) {
            if (answerGroup.getSelection() != null) {
                int selectedAnswer = -1;
                for (int i = 0; i < answerButtons.length; i++) {
                    if (answerButtons[i].isSelected()) {
                        selectedAnswer = i + 1;
                    }
                }
                Question currentQuestion = questionList.get(currentQuestionIndex);
                if (selectedAnswer == currentQuestion.getCorrectAnswer()) {
                    numCorrect++;
                }
                numAnswered++;
                if (numAnswered == questionList.size()) {
                    JOptionPane.showMessageDialog(frame, "You got " + numCorrect + " out of " + numAnswered + " correct.");
                    nextButton.setEnabled(false);
                    restartButton.setEnabled(true);
                } else {
                    currentQuestionIndex++;
                    displayCurrentQuestion();
                }
            }
        } else if (e.getSource() == restartButton) {
            currentQuestionIndex = 0;
            numCorrect = 0;
            numAnswered = 0;
            displayCurrentQuestion();
            nextButton.setEnabled(true);
            restartButton.setEnabled(false);
        }
    }

    private void displayCurrentQuestion() {
        Question currentQuestion = questionList.get(currentQuestionIndex);
        questionLabel.setText(currentQuestion.getQuestionText());
        String[] answers = currentQuestion.getAnswers();
        for (int i = 0; i < answerButtons.length; i++) {
            answerButtons[i].setText(answers[i]);
            answerButtons[i].setSelected(false);
        }
    }

    private static class Question {

        private final String questionText;
        private final String[] answers;
        private final int correctAnswer;

        public Question(String questionText, String[] answers, int correctAnswer) {
            this.questionText = questionText;
            this.answers = answers;
            this.correctAnswer = correctAnswer;
        }

        public String getQuestionText() {
            return questionText;
        }

        public String[] getAnswers() {
            return answers;
        }

        public int getCorrectAnswer() {
            return correctAnswer;
        }
    }
}

This code uses Swing to create a GUI with buttons, labels, and radio buttons. It also uses a JFileChooser to allow the user to select a file containing the questions. The program reads the questions from the file and stores them in a list of Question objects. The user can then answer the questions one by one, and their score is displayed at the end. The program also includes a "Restart" button to allow the user to start a new quiz.