java

package student.ans;

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

public class MgmtAppAns {
    public static void main(String[] args) {
        StudentDatabase database = new StudentDatabase();

        // Demonstrate adding, updating, and listing students
        Student student1 = new Student("Alice", 20, "Computer Science");
        Student student2 = new Student("Bob", 21, "Engineering");
        database.addStudent(student1);
        database.addStudent(student2);

        Student retrievedStudent = database.getStudent(1);
        retrievedStudent.setName("Alex");
        database.updateStudent(retrievedStudent);

        database.listStudents();
    }
}

class StudentDatabase {
    private Map<Integer, Student> students = new HashMap<>();
    private int nextId = 1;

    public void addStudent(Student student) {
        student.setId(nextId);
        students.put(nextId, student);
        nextId++;
    }

    public Student getStudent(int i) {
        return students.get(i);
    }

    public void updateStudent(Student retrievedStudent) {
        students.put(retrievedStudent.getId(), retrievedStudent);
    }

    public void listStudents() {
        students.values().forEach(x -> {
            System.out.println(x.toString());
        });
    }

}

class Student {
    private int id;
    private String name;
    private int age;
    private String course;

    public Student(String name, int age, String course) {
        this.name = name;
        this.age = age;
        this.course = course;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getCourse() {
        return course;
    }

    public void setCourse(String course) {
        this.course = course;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", course='" + course + '\'' +
                '}';
    }
}