StudentManager.java

import java.util.*;

public class StudentManager {
    private List<Student> students;

    public StudentManager() {
        students = FileHandler.loadFromFile();
    }

    public void addStudent(Student student) {
        students.add(student);
        FileHandler.saveToFile(students);
        System.out.println("Student added successfully.");
    }

    public void displayAllStudents() {
        if (students.isEmpty()) {
            System.out.println("No student records found.");
        } else {
            for (Student s : students) {
                System.out.println(s);
            }
        }
    }

    public Student searchStudentById(String id) {
        for (Student s : students) {
            if (s.getId().equalsIgnoreCase(id)) {
                return s;
            }
        }
        return null;
    }

    public void updateStudent(String id, Scanner sc) {
    Student student = searchStudentById(id);
    if (student != null) {
        sc.nextLine();  // <-- Add this line to consume leftover newline before reading name

        System.out.print("Enter new name: ");
        String name = sc.nextLine();
        student.setName(name);

        System.out.print("Enter new age: ");
        int age = sc.nextInt();
        student.setAge(age);

        sc.nextLine();  // <-- Add this line to consume leftover newline before reading course

        System.out.print("Enter new course: ");
        String course = sc.nextLine();
        student.setCourse(course);

        System.out.print("Enter new marks: ");
        double marks = sc.nextDouble();
        student.setMarks(marks);

        FileHandler.saveToFile(students);
        System.out.println("Student updated successfully.");
    } else {
        System.out.println("Student not found.");
    }
}


    public void deleteStudent(String id) {
        Student student = searchStudentById(id);
        if (student != null) {
            students.remove(student);
            FileHandler.saveToFile(students);
            System.out.println("Student deleted successfully.");
        } else {
            System.out.println("Student not found.");
        }
    }
}