### Class1.cs
```
namespace ClassLibrary1;

public class Table
{
    public int Columns;
    private string[] Title;
    private int[] ColMax;
    private List<String> Rows = new List<string>();
    private string Result;
    public Table(List<String> title) : this(title.Count)
    {
        SetTitle(title.ToArray());
    }
    public Table(string[] title) : this(title.Length)
    {
        SetTitle(title);
    }
    public Table(int columns)
    {
        Columns = columns;
    }
    private void CheckTitle()
    {
        if (Title == null)
        {
            throw new Exception("Title is not set");
        }
    }
    public void SetTitle(List<String> title)
    {
        SetTitle(title.ToArray());
    }
    public void SetTitle(string[] title)
    {
        if (title.Length != Columns)
        {
            throw new Exception("Titles not equal columns");
        }
        else
        {
            Title = title;
            ColMax = new int[Title.Length];
            for (int t = 0; t < Title.Length; t++)
            {
                ColMax[t] = Title[t].Length;
            }
        }
    }
    public void AddRow(List<String> row)
    {
        AddRow(row.ToArray());
    }
    public void AddRow(string[] row)
    {
        CheckTitle();
        for (int r = 0; r < row.Length; r++)
        {
            if (row[r].Length > ColMax[r])
            {
                ColMax[r] = row[r].Length;
            }
            Rows.Add(row[r]);
        }
    }
    public void AddRows(List<String> row, bool withTitle = false)
    {
        AddRows(row.ToArray(), withTitle);
    }
    public void AddRows(string[] row, bool withTitle = false)
    {
        if (withTitle)
        {
            SetTitle(row[..Columns]);
            row = row[Columns..];
        }
        CheckTitle();
        for (int r = 0, i = 0; r < row.Length; r++, i++)
        {
            if (i == ColMax.Length) i = 0;
            if (row[r].Length > ColMax[i])
            {
                ColMax[i] = row[r].Length;
            }
            Rows.Add(row[r]);
        }
    }
    public string PrintTable()
    {
        var RowsT = Rows;
        CheckTitle();

        void PTLine(char cenCorner, char hLine= '═')
        {
            foreach (int e in ColMax)
            {
                Result += new string(hLine, e) + cenCorner;
            }
        }
        
        Result += "\n" + '╔';
        PTLine('╤');
        Result += "\b" + '╗' + "\n" + '║';
        //---
        for (int t = 0; t < Title.Length; t++)
        {
            Result += Title[t] + new string(' ', ColMax[t] - Title[t].Length) + '│';
        }
        Result += "\b" + '║' + "\n" + '╟';
        PTLine('┼', '─');
        Result += "\b" + '╢' + "\n";
        //---
        int drIter = RowsT.Count / Columns;
        for (int dr = 0; dr < drIter; dr++)
        {
            Result += '║';
            for (int r = 0; r < Columns; r++)
            {
                Result += RowsT[r] + new string(' ', ColMax[r] - RowsT[r].Length) + '│';
            }
            RowsT = RowsT[Columns..];
            Result += "\b" + '║' + "\n";
        }

        Result += '╚';
        PTLine('╧');
        Result += "\b" + '╝' + "\n";
        return Result;
    }
}
public class Customer
{
    public string Name { get; set; }
    public int Money { get; set; }
    public int Gbalance { get; set; }
    public Customer(string name, int money, int gbalance)
    {
        Name = name;
        Money = money;
        Gbalance = gbalance;
    }
}
public class Goods
{
    public string Name { get; set; }
    public int Price { get; set; }
    public int Amount { get; set; }
    public string Category { get; set; }
    public Goods(string name, int price, int amount, string category)
    {
        Name = name;
        Price = price;
        Amount = amount;
        Category = category;
    }
}
public class Category
{
    public string Title { get; set; }
    public Category(string title)
    {
        Title = title;
    }
}

public class Seller
{
    public string Name { get; set; }
    public int Reviews { get; set; }
    public List<Goods> GoodsList;
    public Seller(string name, int reviews, List<Goods> goodsList)
    {
        Name = name;
        GoodsList = goodsList;
        Reviews = reviews;
    }

}
```
### Program.cs
```
using ClassLibrary1;
class Program
{
    static int Ask(int end=0, int start=0, bool range = true)
    {
        while (true)
        {
            string ch;
            int choice;
            try
            {
                ch = Console.ReadLine();
                if (ch == ":b") return -1;
                else choice = Convert.ToInt32(ch);
            }
            catch
            {
                Console.Write("Неверный ввод, повторите: ");
                continue;
            }
            if (range && choice <= end && choice >= start) return choice;
            else if (range) Console.Write("Неверный ввод, повторите: ");
            else return choice;
        }
    }

    static void Main(string[] args)
    {
        List<Category> categories = new List<Category>()
        {
            new Category("Brawl Stars"),
            new Category("Roblox"),
            new Category("Minecraft"),
            new Category("Pubg")
        };
        List<Goods> goods = new List<Goods>()
        {
            new Goods("Gems", 100, 123, categories[0].Title),
            new Goods("Robux", 200, 321, categories[1].Title)
        };
        List<Seller> sellers = new List<Seller>()
        {
            new Seller("TopSell", 111, new List<Goods>() { goods[1]}),
            new Seller("GameDealer", 222, new List<Goods>(){goods[0]})
        };

        List<Customer> customers = new List<Customer>()
        {
            new Customer("Maxim", 1000000, 0)
        };
        int indxC;
        void InitTable()
        {
            Table t = new Table(new List<string> { "ID", "Категория", "Товар", "Кол-во", "Цена", "Продавец", "Отзывы" });
            int indx = 1;
            foreach (Seller sellerr in sellers)
            {
                foreach (Goods SelGood in sellerr.GoodsList)
                {
                    if (SelGood.Amount != 0)
                    {
                        t.AddRow(new string[] { indx.ToString(), SelGood.Category, SelGood.Name, SelGood.Amount.ToString(), SelGood.Price.ToString(), sellerr.Name, sellerr.Reviews.ToString() });
                    }
                    indx++;
                }
            }
            indxC = indx-1;
            Console.WriteLine(t.PrintTable());
        }
        while (true)
        {
            start:
            Console.Write("1: Режим просмотра.\n2: Режим создания.\n3: Купить товар.\n4: Баланс.\n(:b для возврата).\nВыберите режим: ");
            int ch = Ask(4, 1);
            if (ch == -1) break;
            switch (ch)
            {
                case 1:
                    InitTable();
                    break;
                case 2:
                    Console.WriteLine("\n\tДобавление товара.");
                    for (int k = 0; k < categories.Count; k++)
                    {
                        Console.WriteLine($"{k + 1}: {categories[k].Title}");
                    }
                    Console.Write("Выберите категорию: ");
                    int ch1 = Ask(categories.Count, 1);
                    if (ch1 == -1) break;
                    Console.WriteLine($"\n\tКатегория - {categories[ch1 - 1].Title}");
                    Console.Write("Название: ");
                    string gName = Console.ReadLine();
                    Console.Write("Количество: ");
                    int gAmount = Ask(range:false);
                    Console.Write("Цена: ");
                    int gPrice = Ask(range: false);
                    goods.Add(new Goods(gName, gPrice, gAmount, categories[ch1 - 1].Title));
                    Console.WriteLine("Товар был успешно добавлен.\n------\n");
                    for (int p = 0; p < sellers.Count; p++)
                    {
                        Console.WriteLine($"{p + 1}: {sellers[p].Name}");
                    }
                    Console.Write("Выберите продавца, которому необходимо добавить товар: ");
                    int ch2 = Ask(sellers.Count, 1);
                    if (ch2 == -1) break;
                    sellers[ch2-1].GoodsList.Add(goods[^1]);
                    Console.WriteLine("Товар был успешно зачислен.\n------\n");
                    break;
                case 3:
                    InitTable();
                    Console.Write("\nВведите номер товара: ");
                    int ch3 = Ask(indxC, 1);
                    if (ch3 == -1) break;
                    Console.Write("Введите количество: ");
                    int ch3_1 = Ask(range: false);
                    if (ch3_1 <= 0) { Console.WriteLine("Количество товара должно быть больше 0"); break; }
                    for (int s = 0, gcount = 1; s < sellers.Count; s++)
                    {
                        for (int j = 0; j < sellers[s].GoodsList.Count; j++, gcount++)
                        {
                            if (gcount == ch3)
                            {
                                if (ch3_1 > sellers[s].GoodsList[j].Amount)
                                {
                                    Console.WriteLine("У продавца недостаточно товара");
                                    goto start;
                                }
                                if (customers[0].Money < sellers[s].GoodsList[j].Price * ch3_1)
                                {
                                    Console.WriteLine("Недостаточно средств");
                                    goto start;
                                }
                                sellers[s].GoodsList[j].Amount = sellers[s].GoodsList[j].Amount-ch3_1;
                                customers[0].Money = customers[0].Money - sellers[s].GoodsList[j].Price*ch3_1;
                                customers[0].Gbalance = customers[0].Gbalance + ch3_1;
                                Console.WriteLine("Вы успешно купили товар, с вашего счета списано {0}\n", sellers[s].GoodsList[j].Price*ch3_1);
                            }
                        }
                    }
                    break;
                case 4:
                    Console.WriteLine("\nВаш баланс: {0} руб\nВаш игровой счет: {1}\n", customers[0].Money, customers[0].Gbalance);
                    break;
            }
        }
    }
}
```