Task_4

        static void Main(string[] args)
        {
            int[] array = new int[1];
            string userInput;
            bool isRunning = true;
            string summCommand = "sum";
            string exitCommand = "exit";

            while (isRunning == true)
            {
                Console.Write("Введите команду: ");
                userInput = Console.ReadLine();

                if (userInput == summCommand)
                {
                    int summ = 0;

                    foreach (var number in array)
                        summ += number;

                    Console.WriteLine(summ);
                }
                else if (userInput == exitCommand)
                {
                    isRunning = false;
                }
                else
                {
                    int userNumber;
                    int[] tempArray;

                    if (int.TryParse(userInput, out userNumber))
                    {
                        tempArray = new int[array.Length + 1];

                        for (int i = 0; i < array.Length; i++)
                        {
                            tempArray[i] = array[i];
                        }

                        tempArray[tempArray.Length - 1] = userNumber;
                        array = tempArray;

                        Console.WriteLine("Введено число " + userNumber);
                    }
                    else
                    {
                        Console.WriteLine("Неверный ввод команды!");
                    }
                }
            }
        }