gistfile1.txt

using System;
using System.Collections.Generic;

namespace HWShopV3
{
    internal class Program
    {
        static void Main(string[] args)
        {
            StockListFactory factory = new StockListFactory();

            Seller seller = new Seller("Васёк", 0, factory.Create());

            Buyer buyer = new Buyer("Женёк", 100, new List<Item>());

            Shop shop = new Shop(seller, buyer);

            buyer.ShowAllInfo();
            seller.ShowAllInfo();

            shop.MakeDeal();

            buyer.ShowAllInfo();
            seller.ShowAllInfo();
        }
    }

    class Shop
    {
        private Seller _seller;
        private Buyer _buyer;

        public Shop(Seller seller, Buyer buyer)
        {
            _seller = seller;
            _buyer = buyer;
        }

        public void MakeDeal()
        {
            Item item = _seller.OfferChoice();

            if (item != null && _seller.CheckSolvency(item, _buyer))
            {
                _seller.Sell(item);
                _buyer.Buy(item);
            }
            else
            {
                Console.WriteLine("Сделка не состоялась");
            }
        }
    }

    class Human
    {
        protected string Role;
        protected string Name;
        protected int Money;
        protected List<Item> Items;

        public Human(string name, int money, List<Item> items)
        {
            Name = name;
            Money = money;
            Items = items;
        }

        public int GetMoney => Money;

        public void ShowAllInfo()
        {
            Console.Write($"Меня зовут {Name}, я {Role}, у меня ");
            ShowMoney();
            ShowInventory();
        }

        private void ShowMoney()
        {
            Console.WriteLine($"осталось {Money} монет");
        }

        private void ShowInventory()
        {
            Console.WriteLine("У меня в инвентаре:");

            if (Items.Count == 0)
            {
                Console.WriteLine("Пустота");
            }
            else
            {
                foreach (Item item in Items)
                {
                    Console.WriteLine($"{item.Name}, цена - {item.Price} монет");
                }
            }
        }
    }

    class Seller : Human
    {
        public Seller(string name, int money, List<Item> items) : base(name, money, items)
        {
            Role = "продавец";
        }

        public Item OfferChoice()
        {
            int chosenIndex;

            Console.WriteLine("Что приглянулось?");

            for (int i = 0; i < Items.Count; i++)
            {
                Console.WriteLine($"{i + 1}: {Items[i].Name}");
            }

            Console.WriteLine($"{Items.Count + 1} - {int.MaxValue}: Ничего");

            chosenIndex = Utils.ReadInt();

            if (chosenIndex > 0 && chosenIndex <= Items.Count)
            {
                int index = chosenIndex - 1;

                return GetItem(index);
            }
            else
            {
                Console.WriteLine("Выбрано ничего.\nПотрачено 0 денег, заходите ещё. Или нет.");

                return null;
            }
        }

        public bool CheckSolvency(Item item, Buyer buyer)
        {
            if (item.Price <= buyer.GetMoney)
            {
                return true;
            }
            else
            {
                Console.WriteLine("Не хватат");
                return false;
            }
        }

        public void Sell(Item item)
        {
            int price = item.Price;

            Items.Remove(item);
            TakeMoney(price);
        }

        private void TakeMoney(int money)
        {
            Money += money;
        }

        private Item GetItem(int index)
        {
            Item item = Items[index];

            return item;
        }
    }

    class Buyer : Human
    {
        public Buyer(string name, int money, List<Item> items) : base(name, money, items)
        {
            Role = "покупатель";
        }

        public void Buy(Item item)
        {
            int price = item.Price;

            GiveMoney(price);
            TakeItem(item);
        }

        private void TakeItem(Item item)
        {
            Items.Add(item);
        }

        private void GiveMoney(int price)
        {
            Money -= price;
        }
    }

    class StockListFactory
    {
        private int _quantityEveryFruit;
        private List<Item> _items;

        public StockListFactory()
        {
            SetFruits();
            SetQuantity();
        }

        public List<Item> Create()
        {
            List<Item> items = new List<Item>();

            for (int i = 0; i < _items.Count; i++)
            {
                for (int j = 0; j < _quantityEveryFruit; j++)
                {
                    items.Add(new Item(_items[i].Name, _items[i].Price));
                }
            }

            return items;
        }

        private void SetFruits()
        {
            _items = new List<Item>
            {
               new Item("Яблоко", 5),
               new Item("Апельсин", 150),
               new Item("Лимон", 8)
            };
        }

        private void SetQuantity()
        {
            _quantityEveryFruit = 3;
        }
    }

    class Item
    {
        public Item(string name, int price)
        {
            Name = name;
            Price = price;
        }

        public string Name { get; private set; }

        public int Price { get; private set; }
    }

    static class Utils
    {
        public static int ReadInt()
        {
            int number;

            do
            {
                Console.WriteLine("Введите номер.");
            }
            while (int.TryParse(Console.ReadLine(), out number) == false);

            return number;
        }
    }
}