private String trainName;

private String source;

private String destination;

public Train(String trainName, String source, String destination) {

this.trainName = trainName;

this.source = source;

this.destination = destination;

}

public String getTrainName() {

return trainName;

}

public String getSource() {

return source;

}

public String getDestination() {

return destination;

}

private Map<String, Train> trains;

private Map<String, String> users;

public ReservationSystem() {

trains = new HashMap<>();

users = new HashMap<>();

// Adding some sample trains

trains.put("123", new Train("Express 123", "City A", "City B"));

trains.put("456", new Train("Superfast 456", "City C", "City D"));

trains.put("789", new Train("Local 789", "City E", "City F"));

}

public boolean registerUser(String username, String password) {

if (users.containsKey(username)) {

System.out.println("Username already exists!");

return false;

}

users.put(username, password);

System.out.println("Registration successful!");

return true;

}

public boolean loginUser(String username, String password) {

if (users.containsKey(username) && users.get(username).equals(password)) {

System.out.println("Login successful!");

return true;

}

System.out.println("Invalid username or password!");

return false;

}

public void displayTrainDetails() {

System.out.println("Available Trains:");

System.out.println("Train Number\tTrain Name\tSource\t\tDestination");

for (Map.Entry<String, Train> entry : trains.entrySet()) {

Train train = entry.getValue();

System.out.println(entry.getKey() + "\t\t" + train.getTrainName() + "\t" + train.getSource() + "\t\t" + train.getDestination());

}

}

public void cancelReservation(String username) {

// Perform cancellation logic here

System.out.println("Reservation cancelled for user: " + username);

}

public static void main(String[] args) {

ReservationSystem reservationSystem = new ReservationSystem();

Scanner scanner = new Scanner(System.in);

while (true) {

System.out.println("\n*** Online Reservation System ***");

System.out.println("1. Register");

System.out.println("2. Login");

System.out.println("3. Display Train Details");

System.out.println("4. Cancel Reservation");

System.out.println("5. Exit");

System.out.print("Enter your choice: ");

int choice = scanner.nextInt();

scanner.nextLine(); // Consume newline character

switch (choice) {

case 1:

System.out.print("Enter username: ");

String registerUsername = scanner.nextLine();

System.out.print("Enter password: ");

String registerPassword = scanner.nextLine();

reservationSystem.registerUser(registerUsername, registerPassword);

break;

case 2:

System.out.print("Enter username: ");

String loginUsername = scanner.nextLine();

System.out.print("Enter password: ");

String loginPassword = scanner.nextLine();

if (reservationSystem.loginUser(loginUsername, loginPassword)) {

while (true) {

System.out.println("\n*** Welcome, " + loginUsername + "! ***");

System.out.println("1. Display Train Details");

System.out.println("2. Cancel Reservation");

System.out.println("3. Logout");

System.out.print("Enter your choice: ");

int userChoice = scanner.nextInt();

scanner.nextLine(); // Consume newline character

switch (userChoice) {

case 1:

reservationSystem.displayTrainDetails();

break;

case 2:

reservationSystem.cancelReservation(loginUsername);

break;

case 3:

System.out.println("Logged out successfully!");

break;

default:

System.out.println("Invalid choice!");

break;

}

if (userChoice == 3) {

break; // Exit the inner loop and go back to the main menu

}

}

}

break;

case 3:

reservationSystem.displayTrainDetails();

break;

case 4:

System.out.print("Enter username: ");

String cancelUsername = scanner.nextLine();

reservationSystem.cancelReservation(cancelUsername);

break;

case 5:

System.out.println("Exiting... Thank you!");

System.exit(0);

break;

default:

System.out.println("Invalid choice!");

break;

}

}

}