StudentManagementSystem.java

import java.util.ArrayList;
import java.util.Scanner;

class Student {
    private String rollNumber;
    private String name;
    private String course;
    private double marks;
    private String grade;

    public void inputStudent(Scanner scanner) {
        System.out.print("Enter student's roll number: ");
        this.rollNumber = scanner.nextLine();
        System.out.print("Enter student's name: ");
        this.name = scanner.nextLine();
        System.out.print("Enter student's course: ");
        this.course = scanner.nextLine();

        while (true) {
            try {
                System.out.print("Enter marks (0-100): ");
                this.marks = Double.parseDouble(scanner.nextLine());
                if (this.marks >= 0 && this.marks <= 100) {
                    break;
                } else {
                    System.out.println("Invalid marks. Please enter a value between 0 and 100.");
                }
            } catch (NumberFormatException e) {
                System.out.println("Invalid input. Please enter a number for marks.");
            }
        }
    }

    public void calculateGrade() {
        if (marks >= 90) {
            grade = "A";
        } else if (marks >= 80) {
            grade = "B";
        } else if (marks >= 70) {
            grade = "C";
        } else if (marks >= 60) {
            grade = "D";
        } else {
            grade = "F";
        }
    }

    public void displayStudent() {
        
        System.out.println("Roll Number: " + rollNumber);
        System.out.println("Name: " + name);
        System.out.println("Course: " + course);
        System.out.println("Marks: " + marks);
        System.out.println("Grade: " + grade);
        
    }
}

public class StudentManagementSystem {
    private ArrayList<Student> students;
    private Scanner scanner;

    public StudentManagementSystem() {
        students = new ArrayList<>();
        scanner = new Scanner(System.in);
    }

    public void addStudent() {
        Student student = new Student();
        student.inputStudent(scanner);
        student.calculateGrade();
        students.add(student);
        System.out.println("\nStudent record added successfully!\n");
    }

    public void displayAllStudents() {
        if (students.isEmpty()) {
            System.out.println("\nNo student records to display.\n");
            return;
        }

        System.out.println("\n--- All Student Records ---\n");
        for (Student student : students) {
            student.displayStudent();
        
    }

    public void showMenu() {
        while (true) {
            System.out.print("\033[H\033[2J");
            System.out.flush();
            
            System.out.println("  Student Management System   ");
           
            System.out.println("1. Add a new student record");
            System.out.println("2. Display all student records");
            System.out.println("3. Exit");
            
            System.out.print("Enter your choice (1-3): ");

            String choice = scanner.nextLine();

            switch (choice) {
                case "1":
                    addStudent();
                    System.out.println("Press Enter to continue...");
                    scanner.nextLine();
                    break;
                case "2":
                    displayAllStudents();
                    System.out.println("Press Enter to continue...");
                    scanner.nextLine();
                    break;
                case "3":
                    System.out.println("\nExiting the program. Goodbye!");
                    return;
                default:
                    System.out.println("\nInvalid choice. Please try again.");
                    System.out.println("Press Enter to continue...");
                    scanner.nextLine();
                    break;
            }
        }
    }

    public static void main(String[] args) {
        StudentManagementSystem system = new StudentManagementSystem();
        system.showMenu();
    }
}