using System;

using System.Collections.Generic;

​

class ShoppingListManager

{

    static void Main()

    {

        string[] essentialItems = new string[5]; // Fixed-size array

        List<string> regularItems = new List<string>(); // Dynamic list

​

        while (true)

        {

            Console.WriteLine("\nShopping List Manager");

            Console.WriteLine("--------------------");

​

            // Display Lists

            Console.WriteLine("\nEssential Items (Fixed: 5 slots):");

            int usedSlots = 0;

            for (int i = 0; i < essentialItems.Length; i++)

            {

                if (!string.IsNullOrEmpty(essentialItems[i]))

                {

                    Console.WriteLine($"{i + 1}. {essentialItems[i]}");

                    usedSlots++;

                }

            }

            Console.WriteLine($"[{essentialItems.Length - usedSlots} slots remaining]");

​

            Console.WriteLine("\nRegular Items (Dynamic):");

            for (int i = 0; i < regularItems.Count; i++)

            {

                Console.WriteLine($"{i + 1}. {regularItems[i]}");

            }

​

            Console.WriteLine("\nEnter command (1-Add, 2-Remove, 3-Search, 4-Display, 5-Exit): ");

            string input = Console.ReadLine();

​

            if (!int.TryParse(input, out int choice))

            {

                Console.WriteLine("Invalid input. Please enter a number.");

                continue;

            }

​

            if (choice == 1) // Add Item

            {

                Console.WriteLine("Add to: (1-Essential, 2-Regular): ");

                string listInput = Console.ReadLine();

                if (!int.TryParse(listInput, out int listChoice)) continue;

​

                Console.Write("Enter item: ");

                string item = Console.ReadLine();

​

                if (string.IsNullOrEmpty(item))

                {

                    Console.WriteLine("Item cannot be empty!");

                    continue;

                }

​

                if (listChoice == 1) // Add to Essential

                {

                    bool added = false;

                    for (int i = 0; i < essentialItems.Length; i++)

                    {

                        if (string.IsNullOrEmpty(essentialItems[i]))

                        {

                            essentialItems[i] = item;

                            Console.WriteLine($"Added '{item}' to Essential Items!");

                            added = true;

                            break;

                        }

                    }

                    if (!added)

                    {

                        Console.WriteLine("Essential Items list is full!");

                    }

                }

                else if (listChoice == 2) // Add to Regular

                {

                    regularItems.Add(item);

                    Console.WriteLine($"Added '{item}' to Regular Items!");

                }

                else

                {

                    Console.WriteLine("Invalid choice.");

                }

            }

            else if (choice == 2) // Remove Item

            {

                if (regularItems.Count == 0)

                {

                    Console.WriteLine("Regular Items list is empty!");

                    continue;

                }

​

                Console.Write("Enter item to remove: ");

                string item = Console.ReadLine();

​

                if (regularItems.Remove(item))

                {

                    Console.WriteLine($"Removed '{item}' from Regular Items.");

                }

                else

                {

                    Console.WriteLine("Item not found in Regular Items.");

                }

            }

            else if (choice == 3) // Search Item

            {

                Console.Write("Enter item to search: ");

                string item = Console.ReadLine();

                bool found = false;

​

                // Search in Essential Items

                foreach (var essential in essentialItems)

                {

                    if (essential != null && essential.Equals(item, StringComparison.OrdinalIgnoreCase))

                    {

                        Console.WriteLine($"'{item}' found in Essential Items.");

                        found = true;

                        break;

                    }

                }

​

                // Search in Regular Items (without using Any())

                foreach (var regular in regularItems)

                {

                    if (regular.Equals(item, StringComparison.OrdinalIgnoreCase))

                    {

                        Console.WriteLine($"'{item}' found in Regular Items.");

                        found = true;

                        break;

                    }

                }

​

                if (!found)

                {

                    Console.WriteLine($"'{item}' not found in any list.");

                }

            }

            else if (choice == 4) // Display Lists Again

            {

                Console.WriteLine("\nPress any key to continue...");

                Console.ReadKey();

            }

            else if (choice == 5) // Exit

            {

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

                break;

            }

            else

            {

                Console.WriteLine("Invalid choice. Try again.");

            }

        }

    }

}

​