static void Main(string[] args)
        {
            Double         currentVar = 0;
            Boolean        flag       = true;
            string         state      = "";
            string         str;
            Queue <Double> queue = new Queue <Double>();

            while (flag)
            {
                Console.WriteLine("Hello, do you want to choose option?");
                string option = Console.ReadLine();
                if (option.Equals("Yes"))
                {
                    state = Console.ReadLine();
                }
                switch (state)
                {
                case "Add":
                    while (true)
                    {
                        Console.WriteLine("Enter value");
                        str = Console.ReadLine();
                        if (Program.Check(str))
                        {
                            queue.Enqueue(Double.Parse(str));
                        }
                        Console.WriteLine("Do you want to stop?");
                        str = Console.ReadLine();
                        if (str.Equals("Yes"))
                        {
                            break;
                        }
                    }
                    break;

                case "Single":
                    SingleOp op = new SingleOp();

                    Console.WriteLine(currentVar);
                    currentVar = op.Action(currentVar);

                    break;

                case "Multiple":
                    List <Double> list = new List <Double>();
                    foreach (Double var in queue)
                    {
                        list.Add(var);
                    }
                    MultipleOp multipleOp = new MultipleOp();
                    multipleOp.Action(currentVar, list);
                    break;

                case "Binary":
                    BinaryOp binOp = new BinaryOp();
                    Double   secondVar;
                    secondVar  = queue.Dequeue();
                    currentVar = binOp.Action(currentVar, secondVar);
                    break;

                case "Exit":
                    flag = false;
                    break;

                case "Clear":
                    currentVar = 0;
                    break;

                case "Change":
                    bool numb = true;
                    Console.WriteLine("Enter value");
                    while (numb)
                    {
                        str = Console.ReadLine();
                        if (Program.Check(str))
                        {
                            currentVar = Double.Parse(str);
                            numb       = false;
                        }
                        else
                        {
                            Console.WriteLine("Incorrect value");
                        }
                    }
                    break;
                }
                Console.WriteLine(currentVar);
            }
        }