RecordSystem.java

//import java.util.*;
import java.util.ArrayList;
import java.util.Scanner;

class Student {
    private int id;
    private String name;
    private double marks;

    public Student(int id, String name, double marks) {
        this.id = id;
        this.name = name;
        this.marks = marks;
    }

    public int getId() {
         return id; 
        }
    public String getName() {
         return name; 
        }
    public double getMarks() {
         return marks; 
        }

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

    @Override
    public String toString() {
        return "ID: " + id + ", Name: " + name + ", Marks: " + marks;
    }
}

public class RecordSystem {
    private static ArrayList<Student> students = new ArrayList<>();
    private static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        while (true) {
            System.out.println("\n1. Add Student\n2. View Students\n3. Update Student\n4. Delete Student\n5. Exit");
            System.out.print("Choose option: ");
            int choice = sc.nextInt();
            switch (choice) {
                case 1: addStudent(); 
                break;
                case 2: viewStudents();
                break;
                case 3: updateStudent();
                break;
                case 4: deleteStudent();
                break;
                case 5: System.exit(0);
                default: System.out.println("Invalid option.");
            }
        }
    }

    private static void addStudent() {
        System.out.print("Enter ID: ");
        int id = sc.nextInt();
        sc.nextLine(); // consume newline
        System.out.print("Enter Name: ");
        String name = sc.nextLine();
        System.out.print("Enter Marks: ");
        double marks = sc.nextDouble();
        students.add(new Student(id, name, marks));
        System.out.println("Student added.");
    }

    private static void viewStudents() {
        if (students.isEmpty()) {
            System.out.println("No students found.");
            return;
        }
        for (Student s : students) {
            System.out.println(s);
        }
    }

    private static void updateStudent() {
        System.out.print("Enter ID to update: ");
        int id = sc.nextInt();
        for (Student s : students) {
            if (s.getId() == id) {
                sc.nextLine(); // consume newline
                System.out.print("Enter new Name: ");
                String name = sc.nextLine();
                System.out.print("Enter new Marks: ");
                double marks = sc.nextDouble();
                s.setName(name);
                s.setMarks(marks);
                System.out.println("Student updated.");
                return;
            }
        }
        System.out.println("Student not found.");
    }

    private static void deleteStudent() {
        System.out.print("Enter ID to delete: ");
        int id = sc.nextInt();
        for (int i = 0; i < students.size(); i++) {
            if (students.get(i).getId() == id) {
                students.remove(i);
                System.out.println("Student deleted.");
                return;
            }
        }
        System.out.println("Student not found.");
    }
}