IMEE Simple Java Program Example

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

class User {
    private String email;
    private String password;
    private String username;

    public User(String email, String password, String username) {
        this.email = email;
        this.password = password;
        this.username = username;
    }

    public String getEmail() {
        return email;
    }

    public String getPassword() {
        return password;
    }

    public String getUsername() {
        return username;
    }
}

class UserManager {
    private List<User> users = new ArrayList<>();

    public void registerUser(String email, String password, String username) {
        users.add(new User(email, password, username));
        System.out.println("Registration successful!");
    }

    public User loginUser(String email, String password) {
        for (User user : users) {
            if (user.getEmail().equals(email) && user.getPassword().equals(password)) {
                return user;
            }
        }
        return null; // User not found
    }
}

public class UserRegistrationApp {
    public static void main(String[] args) {
        UserManager userManager = new UserManager();
        Scanner scanner = new Scanner(System.in);

        while (true) {
            System.out.println("1. Register");
            System.out.println("2. Login");
            System.out.println("3. Exit");
            System.out.print("Choose an option: ");
            int choice = scanner.nextInt();
            scanner.nextLine(); // Consume the newline character

            if (choice == 1) {
                System.out.print("Enter your email: ");
                String email = scanner.nextLine();
                System.out.print("Enter your password: ");
                String password = scanner.nextLine();
                System.out.print("Enter your username: ");
                String username = scanner.nextLine();
                userManager.registerUser(email, password, username);
            } else if (choice == 2) {
                System.out.print("Enter your email: ");
                String email = scanner.nextLine();
                System.out.print("Enter your password: ");
                String password = scanner.nextLine();
                User user = userManager.loginUser(email, password);
                if (user != null) {
                    System.out.println("Welcome, " + user.getUsername() + "!");
                    // You can display the logged-in page here.
                } else {
                    System.out.println("Invalid email or password. Please try again.");
                }
            } else if (choice == 3) {
                break;
            } else {
                System.out.println("Invalid choice. Please try again.");
            }
        }

        scanner.close();
    }
}