using System;

namespace homework
{
    class Program
    {
        static void Main(string[] args)
        {
            string str = "", clickToNext = "Нажмите для продолжения...\n";
            while (true)
            {
                Console.Write("1. Сложение целых чисел\n2. Вычитание целых чисел\n3. Умножение целых чисел\n4. Деление целых чисел\n5. История\n6. Выход\nВведите номер команды: ");

                int number = Convert.ToInt32(Console.ReadLine());
                int summ = 0, first = 0, second = 0;
                switch (number)
                {
                    case 1:
                        Console.Clear();
                        while (true)
                        {
                            ConsoleKeyInfo CharKey = Console.ReadKey(true);
                            if (CharKey.Key == ConsoleKey.Enter)
                            {
                                summ++;
                                if (summ > 1)
                                {
                                    Console.WriteLine(" = "+(first+second));
                                    Console.WriteLine(clickToNext);
                                    str += first + " + "+second +" = " + (first + second)+"\n";
                                    Console.ReadKey();
                                    break;
                                }
                                else Console.Write(" + ");
                            }
                            else
                            {
                                if (CharKey.KeyChar >= '0' || CharKey.KeyChar <= '9')
                                {
                                    Console.Write(CharKey.KeyChar);
                                    if (summ == 0)
                                    {
                                        first = first * 10 + CharKey.KeyChar - '0';
                                    }
                                    else
                                    {
                                        second = second * 10 + CharKey.KeyChar - '0';
                                    }
                                }
                            }
                        }
                        Console.Clear();
                        break;
                    case 2:
                        Console.Clear();
                        while (true)
                        {
                            ConsoleKeyInfo CharKey = Console.ReadKey(true);
                            if (CharKey.Key == ConsoleKey.Enter)
                            {
                                summ++;
                                if (summ > 1)
                                {
                                    Console.WriteLine(" = " + (first - second));
                                    Console.WriteLine(clickToNext);
                                    str += first + " - " + second + " = " + (first - second) + "\n";
                                    Console.ReadKey();
                                    break;
                                }
                                else Console.Write(" - ");
                            }
                            else
                            {
                                if (CharKey.KeyChar >= '0' || CharKey.KeyChar <= '9')
                                {
                                    Console.Write(CharKey.KeyChar);
                                    if (summ == 0)
                                    {
                                        first = first * 10 + CharKey.KeyChar - '0';
                                    }
                                    else
                                    {
                                        second = second * 10 + CharKey.KeyChar - '0';
                                    }
                                }
                            }
                        }
                        Console.Clear();
                        break;
                    case 3:
                        Console.Clear();
                        while (true)
                        {
                            ConsoleKeyInfo CharKey = Console.ReadKey(true);
                            if (CharKey.Key == ConsoleKey.Enter)
                            {
                                summ++;
                                if (summ > 1)
                                {
                                    Console.WriteLine(" = " + (first * second));
                                    Console.WriteLine(clickToNext);
                                    str += first + " * " + second + " = " + (first * second) + "\n";
                                    Console.ReadKey();
                                    break;
                                }
                                else Console.Write(" * ");
                            }
                            else
                            {
                                if (CharKey.KeyChar >= '0' || CharKey.KeyChar <= '9')
                                {
                                    Console.Write(CharKey.KeyChar);
                                    if (summ == 0)
                                    {
                                        first = first * 10 + CharKey.KeyChar - '0';
                                    }
                                    else
                                    {
                                        second = second * 10 + CharKey.KeyChar - '0';
                                    }
                                }
                            }
                        }
                        Console.Clear();
                        break;
                    case 4:
                        Console.Clear();
                        while (true)
                        {
                            ConsoleKeyInfo CharKey = Console.ReadKey(true);
                            if (CharKey.Key == ConsoleKey.Enter)
                            {
                                summ++;
                                if (summ > 1)
                                {
                                    Console.WriteLine(" = " + (first / second));
                                    Console.WriteLine(clickToNext);
                                    str += first + " / " + second + " = " + (first / second) + "\n";
                                    Console.ReadKey();
                                    break;
                                }
                                else Console.Write(" / ");
                            }
                            else
                            {
                                if (CharKey.KeyChar >= '0' || CharKey.KeyChar <= '9')
                                {
                                    Console.Write(CharKey.KeyChar);
                                    if (summ == 0)
                                    {
                                        first = first * 10 + CharKey.KeyChar - '0';
                                    }
                                    else
                                    {
                                        second = second * 10 + CharKey.KeyChar - '0';
                                    }
                                }
                            }
                        }
                        Console.Clear();
                        break;
                    case 5:
                        Console.Clear();
                        Console.WriteLine(str);
                        Console.WriteLine("\n" + clickToNext);
                        Console.ReadKey();
                        Console.Clear();
                        break;
                    case 6:
                    default:
                        Console.WriteLine("Выход...");
                        return;
                }
            }
        }
    }
}