Java实现学生选课系统

学生选课系统可以使用 Java 实现，以下是一个简单的实现示例：

1. 定义学生类

public class Student {
    private int id;
    private String name;
    private List<Course> courses;

    public Student(int id, String name) {
        this.id = id;
        this.name = name;
        this.courses = new ArrayList<>();
    }

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public List<Course> getCourses() {
        return courses;
    }

    public void addCourse(Course course) {
        courses.add(course);
    }

    public void removeCourse(Course course) {
        courses.remove(course);
    }
}

2. 定义课程类

public class Course {
    private int id;
    private String name;
    private int capacity;
    private List<Student> students;

    public Course(int id, String name, int capacity) {
        this.id = id;
        this.name = name;
        this.capacity = capacity;
        this.students = new ArrayList<>();
    }

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public int getCapacity() {
        return capacity;
    }

    public List<Student> getStudents() {
        return students;
    }

    public boolean addStudent(Student student) {
        if (students.size() < capacity) {
            students.add(student);
            student.addCourse(this);
            return true;
        }
        return false;
    }

    public void removeStudent(Student student) {
        students.remove(student);
        student.removeCourse(this);
    }
}

3. 定义选课系统类

public class CourseSelectionSystem {
    private List<Student> students;
    private List<Course> courses;

    public CourseSelectionSystem() {
        this.students = new ArrayList<>();
        this.courses = new ArrayList<>();
    }

    public void addStudent(Student student) {
        students.add(student);
    }

    public void addCourse(Course course) {
        courses.add(course);
    }

    public boolean enroll(int studentId, int courseId) {
        Student student = getStudent(studentId);
        Course course = getCourse(courseId);
        if (student != null && course != null) {
            return course.addStudent(student);
        }
        return false;
    }

    public boolean drop(int studentId, int courseId) {
        Student student = getStudent(studentId);
        Course course = getCourse(courseId);
        if (student != null && course != null) {
            course.removeStudent(student);
            return true;
        }
        return false;
    }

    private Student getStudent(int studentId) {
        for (Student student : students) {
            if (student.getId() == studentId) {
                return student;
            }
        }
        return null;
    }

    private Course getCourse(int courseId) {
        for (Course course : courses) {
            if (course.getId() == courseId) {
                return course;
            }
        }
        return null;
    }
}

使用示例：

// 创建学生和课程
Student s1 = new Student(1, "Alice");
Student s2 = new Student(2, "Bob");
Course c1 = new Course(1, "Java Programming", 3);
Course c2 = new Course(2, "Data Structures", 2);

// 添加学生和课程到选课系统
CourseSelectionSystem system = new CourseSelectionSystem();
system.addStudent(s1);
system.addStudent(s2);
system.addCourse(c1);
system.addCourse(c2);

// 学生选课
system.enroll(1, 1); // Alice选Java Programming课，成功
system.enroll(1, 2); // Alice选Data Structures课，成功
system.enroll(2, 1); // Bob选Java Programming课，成功
system.enroll(2, 2); // Bob选Data Structures课，失败，因为课程已满

// 学生退课
system.drop(1, 2); // Alice退掉Data Structures课

这只是一个简单的实现示例，实际的选课系统可能需要更多的功能和复杂性。