import java.util.HashMap;
import java.util.Scanner;

public class LoginWithRegistration {
private static HashMap users = new HashMap<>();
private static Scanner scanner = new Scanner(System.in);

public static void main(String[] args) { // Add default users users.put("admin", "admin123"); while (true) { System.out.println("\n=== MAIN MENU ==="); System.out.println("1. Login"); System.out.println("2. Register"); System.out.println("3. Exit"); System.out.print("Choose option: "); int choice = scanner.nextInt(); scanner.nextLine(); // Consume newline switch (choice) { case 1: login(); break; case 2: register(); break; case 3: System.out.println("Goodbye!"); scanner.close(); return; default: System.out.println("Invalid option!"); } } } private static void login() { System.out.println("\n--- LOGIN ---"); System.out.print("Username: "); String username = scanner.nextLine(); System.out.print("Password: "); String password = scanner.nextLine(); if (users.containsKey(username) && users.get(username).equals(password)) { System.out.println("✓ Login successful! Welcome " + username + "!"); } else { System.out.println("✗ Invalid username or password!"); } } private static void register() { System.out.println("\n--- REGISTRATION ---"); System.out.print("Choose username: "); String username = scanner.nextLine(); if (users.containsKey(username)) { System.out.println("✗ Username already exists!"); return; } System.out.print("Choose password: "); String password = scanner.nextLine(); users.put(username, password); System.out.println("✓ Registration successful! You can now login."); }