(2022级）成都工业学院Java程序设计（JAVA）实验二：类和对象

写在前面

1、基于2022级软件工程/计算机科学与技术实验指导书

2、代码仅提供参考

3、如果代码不满足你的要求，请寻求其他的途径

运行环境

window11家庭版

IntelliJ IDEA 2023.2.2

jdk17.0.6

实验要求

1、控制台菜单。在 Exp02_x 类中添加一个方法 menu_x，其他要求要同实验 01-1。

2、编写一个矩形类 Exp02Rectangle_x，要求如下：

1）矩形的宽度和高度由构造方法来确定，要求长和高的范围为 0~30。为此类的方法有 getArea_x 返回矩形的面积；getPerimeter_x 返回矩形的周长；draw_x 使用星号（*）作为描绘字符画出该矩形。

2）在 Exp02_x 类中添加一个方法 rectangleExec_x 调用 Exp02Rectangle_x 对象的方法，它被 menu_x 调用。

3、编写一个三角形类 Exp02Triangle_x，要求如下：

1）能根据三个实数（范围为 0~30）构造三角形对象，如果三个实数不满足三角形的条件，则自动构造以最小值为边的等边三角形。输入任意三个数，输出构造的三角形面积。

2）在 Exp02_x 类中添加一个方法 triangleExec_x 调用 Exp02Triangle_x 对象的方法，它被 menu_x 调用。

4、编写一个二维平面上的点的类 Exp02Point_x，要求如下：

1）表示坐标的两个成员变量 x_x，y_x；

2）两个构造方法，不带参数的功能是置成员变量为 0；带参数的传值给成员变量，要使用 this 关键字；

3）定义 distance_x 方法，计算两个坐标点的距离；~~定义 graph_x 方法，参照上面的 draw_x 绘制与两个坐标点有关的图形，如矩形、圆形等（选做，加分）~~

4）在 Exp02_x 类中添加一个方法 pointExec_x 调用 Exp02Point_x 对象的方法，它被 menu_x 调用。

5、设计一个成绩管理系统。要求如下：

1）系统的主要功能有（1）初始化至少三位教师、三门课程、五位同学和 N 个成绩数据，（2）使用教师编号、学生学号登录，（3）教师录入、显示、查询、修改~~、统计（选做）~~成绩，（4）学生查看成绩（同时显示总分和平均分）；

2）新建类文件 Exp02Score_x，类 Exp02Score_x 的成员变量至少有分数。在此类文件中现分别添加：（1）Exp02Teacher_x 类，成员变量至少有教师编号、教师姓名；（2） Exp02Student_x 类，成员变量至少有学生学号、学生姓名；（3）Exp02Course_x 类，成员变量至少有课程编号、课程名称。根据自己的理解，为前述 4 个类设计成员方法以实现 1）中的功能；

3）新建类文件 Exp02ScoreManage_x，类 Exp02ScoreManage_x 的主要功能初始化数据和用方法 scoreManageExec_x 调用 2）中各个（不一定是所有）类的成员方法，它被 menu_x 调用以及其他方法；

4）其他要求：（1）定义的成员变量必须在恰当的地方使用；（2）要能保证数据合法，如成绩应该在 0~100 之间；录入或修改时超过范围应能提示；（3）功能应该符合逻辑，如教师未录入成绩前，学生应该查询不到成绩等。

源代码

Exp02_x.java

import java.util.Scanner;

//实验题目1：编写一个矩形类
class Exp02Rectangle_x {
    private int width;
    private int height;

    // 构造方法确定矩形的宽度和高度
    public Exp02Rectangle_x(int width, int height) {
        if (width >= 0 && width <= 30 && height >= 0 && height <= 30) {
            this.width = width;
            this.height = height;
        } else {
            System.out.println("宽度和高度必须在0~30之间");
        }
    }

    // 计算矩形的面积
    public int getArea_x() {
        return width * height;
    }

    // 计算矩形的周长
    public int getPerimeter_x() {
        return 2 * (width + height);
    }

    // 绘制矩形
    public void draw_x() {
        for (int i = 0; i < height; i++) {
            for (int j = 0; j < width; j++) {
                System.out.print("*");
            }
            System.out.println();
        }
    }
}

//实验题目2：编写一个三角形类
class Exp02Triangle_x {
    private double side1;
    private double side2;
    private double side3;

    // 构造方法确定三角形的三条边
    public Exp02Triangle_x(double side1, double side2, double side3) {
        // 如果输入的边长不满足三角形的条件，则构造以最小值为边的等边三角形
        if (isValidTriangle(side1, side2, side3)) {
            this.side1 = side1;
            this.side2 = side2;
            this.side3 = side3;
            System.out.println("输入的边长满足条件，按输入的三边长构建三角形");
        } else {
            this.side1 = this.side2 = this.side3 = findShortestSide(side1,side2,side3);
            System.out.println("输入的边长不满足条件，按最小值的边长构建普通三角形");
        }
    }

    // 判断三边是否构成三角形
    private boolean isValidTriangle(double side1, double side2, double side3) {
        return side1 + side2 > side3 && side1 + side3 > side2 && side2 + side3 > side1;
    }
    //找出最小值的边
    private double findShortestSide(double side1,double side2,double side3){
        if (side1<=side2&&side1<=side3){
            return side1;
        }
        else if (side2<=side1&&side2<=side3){
            return side2;
        }
        else {
            return side3;
        }
    }

    // 计算三角形的面积
    public double getArea_x() {
        // 海伦公式计算面积
        double s = (side1 + side2 + side3) / 2;
        return Math.sqrt(s * (s - side1) * (s - side2) * (s - side3));
    }
}

//实验题目3：编写一个二维平面上的点类
class Exp02Point_x {
    private double x_x;
    private double y_x;

    // 不带参数的构造方法，将坐标置为0
    public Exp02Point_x() {
        this.x_x = 0;
        this.y_x = 0;
    }

    // 带参数的构造方法，传值给成员变量
    public Exp02Point_x(double x_x, double y_x) {
        this.x_x = x_x;
        this.y_x = y_x;
    }

    // 计算两个点之间的距离
    public double distance_x(Exp02Point_x other) {
        double dx = this.x_x - other.x_x;
        double dy = this.y_x - other.y_x;
        return Math.sqrt(dx * dx + dy * dy);
    }
}

public class Exp02_x {
    // 调用 Exp02Rectangle_x 对象的方法
    public void rectangleExec_x() {
        Scanner scanner = new Scanner(System.in);
        int width, height;
        // 获取矩形的宽度和高度
        System.out.print("请输入矩形的宽度：");
        width = scanner.nextInt();
        System.out.print("请输入矩形的高度：");
        height = scanner.nextInt();
        // 创建矩形对象
        Exp02Rectangle_x rectangle = new Exp02Rectangle_x(width, height);
        // 输出矩形的面积和周长
        System.out.println("矩形的面积为：" + rectangle.getArea_x());
        System.out.println("矩形的周长为：" + rectangle.getPerimeter_x());
        // 绘制矩形
        System.out.println("绘制的矩形为：");
        rectangle.draw_x();
    }

    // 调用 Exp02Triangle_x 对象的方法
    public void triangleExec_x() {
        Scanner scanner = new Scanner(System.in);
        double side1, side2, side3;
        // 获取三角形的三条边长
        System.out.print("请输入三角形的第一条边长：");
        side1 = scanner.nextDouble();
        System.out.print("请输入三角形的第二条边长：");
        side2 = scanner.nextDouble();
        System.out.print("请输入三角形的第三条边长：");
        side3 = scanner.nextDouble();
        // 创建三角形对象
        Exp02Triangle_x triangle = new Exp02Triangle_x(side1, side2, side3);
        // 输出三角形的面积
        System.out.println("三角形的面积为：" + triangle.getArea_x());
    }

    // 调用 Exp02Point_x 对象的方法
    public void pointExec_x() {
        Scanner scanner = new Scanner(System.in);
        double x1, y1, x2, y2;
        // 获取两个点的坐标
        System.out.print("请输入第一个点的 x 坐标：");
        x1 = scanner.nextDouble();
        System.out.print("请输入第一个点的 y 坐标：");
        y1 = scanner.nextDouble();
        System.out.print("请输入第二个点的 x 坐标：");
        x2 = scanner.nextDouble();
        System.out.print("请输入第二个点的 y 坐标：");
        y2 = scanner.nextDouble();
        // 创建两个点对象
        Exp02Point_x point1 = new Exp02Point_x(x1, y1);
        Exp02Point_x point2 = new Exp02Point_x(x2, y2);
        // 输出两点之间的距离
        System.out.println("两点之间的距离为：" + point1.distance_x(point2));
    }

    // 显示菜单
    public void menu_x() {
        int choice;
        Scanner scanner = new Scanner(System.in);
        while (true) {
            System.out.println("请选择实验题目：");
            System.out.println("0.结束");
            System.out.println("1.编写一个矩形类");
            System.out.println("2.编写一个三角形类");
            System.out.println("3.编写一个二维平面上的点的类");
            System.out.println("4.设计一个成绩管理系统");
            System.out.print("请输入你的选择：");
            choice = scanner.nextInt();
            switch (choice) {
                case 0:
                    System.out.println("程序已退出");
                    return;
                case 1:
                    rectangleExec_x();
                    break;
                case 2:
                    triangleExec_x();
                    break;
                case 3:
                    pointExec_x();
                    break;
                case 4:
                    Exp02ScoreManage_x scoreManage = new Exp02ScoreManage_x();
                    scoreManage.scoreManageExec_x();
                    break;
                default:
                    System.out.println("输入的数据无效，请重新输入");
                    break;
            }
        }
    }
}

Exp02Score_x.java

import java.util.HashMap;
import java.util.Map;

// 实验题目5：设计一个成绩管理系统
class Exp02Teacher_x {
    private String teacherId;
    private String teacherName;
    private String courseId;

    public Exp02Teacher_x(String teacherId, String teacherName, String courseId) {
        this.teacherId = teacherId;
        this.teacherName = teacherName;
        this.courseId = courseId;
    }

    public String getTeacherId() {
        return teacherId;
    }

    public String getTeacherName() {
        return teacherName;
    }

    public String getCourseId() {
        return courseId;
    }
}

// Exp02Student_x 类
class Exp02Student_x {
    private String studentId;
    private String studentName;
    private int score1;
    private int score2;
    private int score3;

    public Exp02Student_x(String studentId, String studentName) {
        this.studentId = studentId;
        this.studentName = studentName;
        this.score1 = -1;
        this.score2 = -1;
        this.score3 = -1;
    }

    public String getStudentId() {
        return studentId;
    }

    public String getStudentName() {
        return studentName;
    }

    public int getScore1() {
        return score1;
    }

    public int getScore2() {
        return score2;
    }

    public int getScore3() {
        return score3;
    }

    public void setScore1(int score1) {
        this.score1 = score1;
    }

    public void setScore2(int score2) {
        this.score2 = score2;
    }

    public void setScore3(int score3) {
        this.score3 = score3;
    }
}

// Exp02Course_x 类
class Exp02Course_x {
    private String courseId;
    private String courseName;

    public Exp02Course_x(String courseId, String courseName) {
        this.courseId = courseId;
        this.courseName = courseName;
    }

    public String getCourseId() {
        return courseId;
    }

    public String getCourseName() {
        return courseName;
    }
}

// Exp02Score_x 类
public class Exp02Score_x {
    private Map<String, Exp02Student_x> students;
    private Map<String, Exp02Teacher_x> teachers;
    private Map<String, Exp02Course_x> courses;
    private Map<String, Integer> scores;

    public Exp02Score_x() {
        students = new HashMap<>();
        teachers = new HashMap<>();
        courses = new HashMap<>();
        scores = new HashMap<>();
    }

    // 初始化学生、老师、课程及成绩
    public void initialize() {
        initializeTeachers();
        initializeStudents();
        initializeCourses();
        initializeScores();
    }

    // 初始化老师
    public void initializeTeachers() {
        teachers.put("T1", new Exp02Teacher_x("T1", "张老师", "C1"));
        teachers.put("T2", new Exp02Teacher_x("T2", "李老师", "C2"));
        teachers.put("T3", new Exp02Teacher_x("T3", "王老师", "C3"));
    }

    // 初始化学生
    public void initializeStudents() {
        students.put("S1", new Exp02Student_x("S1", "小明"));
        students.put("S2", new Exp02Student_x("S2", "小红"));
        students.put("S3", new Exp02Student_x("S3", "小刚"));
        students.put("S4", new Exp02Student_x("S4", "小亮"));
        students.put("S5", new Exp02Student_x("S5", "小美"));
    }

    // 初始化课程
    public void initializeCourses() {
        courses.put("C1", new Exp02Course_x("C1", "语文"));
        courses.put("C2", new Exp02Course_x("C2", "数学"));
        courses.put("C3", new Exp02Course_x("C3", "英语"));
    }

    // 初始化成绩，默认为未录入成绩，显示为-1
    public void initializeScores() {
        for (Exp02Student_x student : students.values()) {
            scores.put(student.getStudentId(), -1);
        }
    }

    // 教师登录
    public boolean teacherLogin(String teacherId) {
        return teachers.containsKey(teacherId);
    }

    // 学生登录
    public boolean studentLogin(String studentId) {
        return students.containsKey(studentId);
    }

    // 录入成绩
    public void addScore(String studentId, int score, String teacherId) {
        Exp02Student_x student = students.get(studentId);
        Exp02Teacher_x teacher = teachers.get(teacherId);
        if (student != null && score >= 0 && score <= 100) {
            String courseId = teacher.getCourseId();
            if (courseId.equals("C1")) {
                student.setScore1(score);
            } else if (courseId.equals("C2")) {
                student.setScore2(score);
            } else if (courseId.equals("C3")) {
                student.setScore3(score);
            }
            System.out.println(student.getStudentName() + "成绩录入成功！");
        } else if (student == null) {
            System.out.println("学生学号不存在！");
        } else {
            System.out.println("成绩录入失败！成绩必须在0到100之间，请重新录入。");
        }
    }


    // 显示学生的成绩
    public void displayStudentScores(String studentId,String teacherId) {
        Exp02Teacher_x teacher=teachers.get(teacherId);
        Exp02Student_x student = students.get(studentId);
        if (student != null) {
            String courseId = teacher.getCourseId();
            Exp02Course_x course=courses.get(courseId);
            if (course != null) {
                if (courseId.equals("C1")) {
                    int score = student.getScore1();
                    if (score == -1) {
                        System.out.println("学生的成绩还未录入！");
                    } else {
                        System.out.println("学生 " + student.getStudentName() + " " + course.getCourseName() + " 的成绩：" + score);
                    }
                } else if (courseId.equals("C2")) {
                    int score = student.getScore2();
                    if (score == -1) {
                        System.out.println("学生的成绩还未录入！");
                    } else {
                        System.out.println("学生 " + student.getStudentName() + " " + course.getCourseName() + " 的成绩：" + score);
                    }
                } else if (courseId.equals("C3")) {
                    int score = student.getScore3();
                    if (score == -1) {
                        System.out.println("学生的成绩还未录入！");
                    } else {
                        System.out.println("学生 " + student.getStudentName() + " " + course.getCourseName() + " 的成绩：" + score);
                    }
                }
            } else {
                System.out.println("课程编号不存在！");
            }
        } else {
            System.out.println("学生学号不存在！");
        }
    }

    // 修改学生成绩
    public void modifyScore(String studentId, int newScore, String teacherId) {
        Exp02Student_x student = students.get(studentId);
        Exp02Teacher_x teacher = teachers.get(teacherId);
        if (student != null && newScore >= 0 && newScore <= 100) {
            String courseId = teacher.getCourseId();
            if (courseId.equals("C1")) {
                student.setScore1(newScore);
            } else if (courseId.equals("C2")) {
                student.setScore2(newScore);
            } else if (courseId.equals("C3")) {
                student.setScore3(newScore);
            }
            System.out.println(student.getStudentName() + "成绩修改成功！");
        } else if (student == null) {
            System.out.println("学生学号不存在！");
        } else {
            System.out.println("成绩修改失败！新成绩必须在0到100之间，请重新输入。");
        }
    }

    // 删除学生成绩
    public void deleteScore(String studentId,String teacherId) {
        Exp02Student_x student = students.get(studentId);
        Exp02Teacher_x teacher = teachers.get(teacherId);
        if (student != null) {
            String courseId=teacher.getCourseId();
            if (courseId.equals("C1")) {
                student.setScore1(-1);
            } else if (courseId.equals("C2")) {
                student.setScore2(-1);
            } else if (courseId.equals("C3")) {
                student.setScore3(-1);
            }
        } else {
            System.out.println("学生学号不存在！");
        }
    }
    // 学生查看所有成绩
    public void displayAllScores(String studentId) {
        Exp02Student_x student = students.get(studentId);
        if (student != null) {
            System.out.println("学生 " + student.getStudentName() + " 的成绩单：");
            if (student.getScore1() != -1) {
                System.out.println("语文成绩：" + student.getScore1());
            } else {
                System.out.println("语文成绩：成绩还未录入");
            }
            if (student.getScore2() != -1) {
                System.out.println("数学成绩：" + student.getScore2());
            } else {
                System.out.println("数学成绩：成绩还未录入");
            }
            if (student.getScore3() != -1) {
                System.out.println("英语成绩：" + student.getScore3());
            } else {
                System.out.println("英语成绩：成绩还未录入");
            }
        } else {
            System.out.println("学生学号不存在！");
        }
    }

    // 计算学生总分
    public int calculateTotalScore(String studentId) {
        Exp02Student_x student = students.get(studentId);
        if (student != null) {
            if (student.getScore1() == -1 || student.getScore2() == -1 || student.getScore3() == -1) {
                return -1; // 表示成绩未录入完毕
            } else {
                return student.getScore1() + student.getScore2() + student.getScore3();
            }
        } else {
            return 0;
        }
    }

    // 计算学生平均分
    public double calculateAverageScore(String studentId) {
        Exp02Student_x student = students.get(studentId);
        if (student != null) {
            int totalScore = calculateTotalScore(studentId);
            if (totalScore == -1) {
                return -1; // 表示成绩未录入完毕
            } else {
                return totalScore / 3.0;
            }
        } else {
            return 0;
        }
    }
}

Exp02ScoreManage_x.java

import java.util.Scanner;

public class Exp02ScoreManage_x {
    private Exp02Score_x scoreManager;

    public Exp02ScoreManage_x() {
        scoreManager = new Exp02Score_x();
        initializeData();
    }

    // 初始化数据
    public void initializeData() {
        scoreManager.initialize();
    }

    // 调用 Exp02Score_x 中各个类的成员方法
    public void scoreManageExec_x() {
        Scanner scanner = new Scanner(System.in);
        int role = 0;
        boolean exitProgram = false;
        while (!exitProgram) {
            System.out.println("请选择您的身份：");
            System.out.println("1. 教师");
            System.out.println("2. 学生");
            System.out.println("-1. 退出程序");
            System.out.printf("你的选择是：");
            role = scanner.nextInt();

            switch (role) {
                case 1:
                    System.out.println("请输入教师编号登录：");
                    String teacherId = scanner.next();
                    if (scoreManager.teacherLogin(teacherId)) {
                        System.out.println("登录成功！");
                        boolean exitTeacherMenu = false;
                        while (!exitTeacherMenu) {
                            System.out.println("请选择操作：");
                            System.out.println("1. 录入学生成绩");
                            System.out.println("2. 显示学生成绩");
                            System.out.println("3. 修改学生成绩");
                            System.out.println("4. 删除学生成绩");
                            System.out.println("0. 返回上一级菜单");
                            System.out.printf("你的选择是：");
                            int choice = scanner.nextInt();
                            switch (choice) {
                                case 1:
                                    System.out.println("请输入学生学号：");
                                    String studentId = scanner.next();
                                    System.out.println("请输入成绩：");
                                    int score = scanner.nextInt();
                                    scoreManager.addScore(studentId, score, teacherId);
                                    break;
                                case 2:
                                    System.out.println("请输入学生学号：");
                                    String queryStudentId = scanner.next();
                                    scoreManager.displayStudentScores(queryStudentId, teacherId);
                                    break;
                                case 3:
                                    System.out.println("请输入学生学号：");
                                    String modifyStudentId = scanner.next();
                                    System.out.println("请输入新的成绩：");
                                    int newScore = scanner.nextInt();
                                    scoreManager.modifyScore(modifyStudentId, newScore, teacherId);
                                    System.out.println("成绩修改成功！");
                                    break;
                                case 4:
                                    System.out.println("请输入学生学号：");
                                    String deleteStudentId = scanner.next();
                                    scoreManager.deleteScore(deleteStudentId, teacherId);
                                    System.out.println("成绩删除成功！");
                                    break;
                                case 0:
                                    exitTeacherMenu = true;
                                    break;
                                default:
                                    System.out.println("请输入有效的操作选项！");
                                    break;
                            }
                        }
                    } else {
                        System.out.println("教师编号不存在！");
                    }
                    break;
                case 2:
                    System.out.println("请输入学生学号登录：");
                    String studentId = scanner.next();
                    if (scoreManager.studentLogin(studentId)) {
                        System.out.println("登录成功！");
                        boolean exitStudentMenu = false;
                        while (!exitStudentMenu) {
                            System.out.println("请选择操作：");
                            System.out.println("1. 查看成绩");
                            System.out.println("0. 返回上一级菜单");
                            System.out.printf("你的选择是：");
                            int choice = scanner.nextInt();
                            switch (choice) {
                                case 1:
                                    scoreManager.displayAllScores(studentId);
                                    int totalScore = scoreManager.calculateTotalScore(studentId);
                                    double averageScore = scoreManager.calculateAverageScore(studentId);
                                    if (totalScore != -1 && averageScore != -1) {
                                        System.out.println("总分：" + totalScore);
                                        System.out.println("平均分：" + averageScore);
                                    } else {
                                        System.out.println("总分：成绩还未录入完毕，请耐心等候！");
                                        System.out.println("平均分：成绩还未录入完毕，请耐心等候！");
                                    }
                                    break;
                                case 0:
                                    exitStudentMenu = true;
                                    break;
                                default:
                                    System.out.println("请输入有效的操作选项！");
                                    break;
                            }
                        }
                    } else {
                        System.out.println("学生学号不存在！");
                    }
                    break;
                case -1:
                    exitProgram = true;
                    System.out.println("程序已退出！");
                    break;
                default:
                    System.out.println("请选择有效的选项！");
                    break;
            }
        }
        scanner.close();
    }
}

Main.java

public class Main {
    public static void main(String[] args) {
        Exp02_x exp02 = new Exp02_x();
        exp02.menu_x(); // 调用菜单方法
    }
}