using System;

using System.Collections.Generic;

​

// Interface for User

interface IUser

{

    string Username { get; set; }

    string Password { get; set; }

}

​

// Interface for Product

interface IProduct

{

    string Name { get; set; }

    double Price { get; set; }

}

​

// Abstract class for Menu Item

abstract class MenuItem

{

    public abstract void Display();

}

​

// Class for User

class User : IUser

{

    public string Username { get; set; }

    public string Password { get; set; }

}

​

// Class for Product

class Product : IProduct

{

    public string Name { get; set; }

    public double Price { get; set; }

}

​

// Main class

class Program

{

    static List<User> users = new List<User>();

    static List<Product> products = new List<Product>();

    static List<Order> orders = new List<Order>();

​

    // User Registration

    static void UserRegistration()

    {

        Console.WriteLine("User Registration");

        Console.Write("Enter username: ");

        string username = Console.ReadLine();

        Console.Write("Enter password: ");

        string password = Console.ReadLine();

​

        users.Add(new User { Username = username, Password = password });

        Console.WriteLine("User registered successfully!");

    }

​

    // Product Registration - Canteen Menu

    static void ProductRegistration()

    {

        Console.WriteLine("Canteen Menu Registration");

        Console.WriteLine("Enter the items for the Canteen Menu:");

​

        Dictionary<string, double> canteenItems = new Dictionary<string, double>

        {

            { "Fries", 20 },

            { "Burger", 30 },

            { "Sandwich", 25 },

            { "Pizza", 15 },

            { "Water", 15 },

            { "Cola", 20 },

            { "Juice", 13 }

        };

​

        foreach (var item in canteenItems)

        {

            Console.WriteLine($"- {item.Key}: ₱{item.Value:F2}");

        }

​

        Console.WriteLine("Enter 'done' when finished.");

​

        while (true)

        {

            Console.Write("Enter item name or 'done': ");

            string itemName = Console.ReadLine().Trim();

​

            if (itemName.ToLower() == "done")

                break;

​

            if (canteenItems.ContainsKey(itemName))

            {

                double itemPriceInPesos = canteenItems[itemName];

​

                products.Add(new Product { Name = itemName, Price = itemPriceInPesos });

                Console.WriteLine($"'{itemName}' added to the Canteen Menu.");

            }

            else

            {

                Console.WriteLine("Invalid item name. Please try again.");

            }

        }

        Console.WriteLine("Canteen Menu updated successfully!");

    }

​

    // User Login

    static bool UserLogin()

    {

        Console.WriteLine("User Login");

        Console.Write("Enter username: ");

        string username = Console.ReadLine();

        Console.Write("Enter password: ");

        string password = Console.ReadLine();

​

        foreach (User user in users)

        {

            if (user.Username == username && user.Password == password)

            {

                Console.WriteLine("Login successful!");

                return true;

            }

        }

​

        Console.WriteLine("Invalid username or password. Please try again.");

        return false;

    }

​

    // Display Menu

    static void DisplayMenu()

    {

        Console.WriteLine("Main Menu");

        Console.WriteLine("1. User Registration");

        Console.WriteLine("2. Product Registration");

        Console.WriteLine("3. User Login");

        Console.WriteLine("4. Search Functionality");

        Console.WriteLine("5. View Record(s)/Report(s)");

        Console.WriteLine("6. Order");

        Console.WriteLine("7. Exit");

    }

​

    // Order Functionality

    static void Order()

    {

        Console.WriteLine("Canteen Menu with Prices in Peso:");

        foreach (Product product in products)

        {

            Console.WriteLine($"{product.Name} - ₱{product.Price:F2}");

        }

​

        Console.WriteLine("Place your order:");

        double total = 0;

        List<string> orderedItems = new List<string>();

​

        while (true)

        {

            Console.Write("Enter item name to order or 'done' to finish: ");

            string itemName = Console.ReadLine().Trim();

​

            if (itemName.ToLower() == "done")

                break;

​

            Product orderedItem = products.Find(p => p.Name.ToLower() == itemName.ToLower());

            if (orderedItem != null)

            {

                total += orderedItem.Price;

                orderedItems.Add(itemName);

                Console.WriteLine($"'{itemName}' added to the order.");

            }

            else

            {

                Console.WriteLine($"'{itemName}' is not available in the menu.");

            }

        }

​

        Console.WriteLine($"Total amount of your order: ₱{total:F2}");

​

        // Save the order

        SaveOrder(total, orderedItems);

    }

​

    // Method to save the order

    static void SaveOrder(double totalAmount, List<string> orderedItems)

    {

        Order order = new Order { TotalAmount = totalAmount, OrderedItems = orderedItems };

        orders.Add(order);

​

        Console.WriteLine("Order Saved:");

        Console.WriteLine($"Total Amount: ₱{totalAmount:F2}");

        Console.WriteLine("Ordered Items:");

        foreach (string item in orderedItems)

        {

            Console.WriteLine(item);

        }

        Console.WriteLine();

    }

​

    // Main method

    static void Main(string[] args)

    {

        bool exit = false;

        while (!exit)

        {

            DisplayMenu();

            Console.Write("Enter your choice: ");

            int choice = Convert.ToInt32(Console.ReadLine());

​

            switch (choice)

            {

                case 1:

                    UserRegistration();

                    break;

                case 2:

                    ProductRegistration();

                    break;

                case 3:

                    UserLogin();

                    break;

                case 4:

                    // Implement search functionality

                    Console.WriteLine("Search Functionality - To be implemented");

                    break;

                case 5:

                    // Implement view records/reports

                    Console.WriteLine("View Record(s)/Report(s) - To be implemented");

                    break;

                case 6:

                    Order();

                    break;

                case 7:

                    exit = true;

                    Console.WriteLine("Exiting program...");

                    break;

                default:

                    Console.WriteLine("Invalid choice. Please try again.");

                    break;

            }

        }

    }

}

​

// Order class to store order details

class Order

{

    public double TotalAmount { get; set; }

    public List<string> OrderedItems { get; set; }

}

​