Task 18

using System;

namespace C_sharp_Light
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] array = new int[0];
            string command;
            bool isOpen = true;

            while (isOpen)
            {
                Console.Clear();
                Console.WriteLine("Числа в памяти:");
                foreach (var number in array)
                {
                    Console.Write(number + " ");
                }
                Console.Write("\n\nВведите или число, или команды sum, exit - ");
                command = Console.ReadLine();

                switch (command)
                {
                    case "sum":
                        int sum = 0;
                        foreach (var number in array)
                        {
                            Console.Write(number + "+");
                            sum += number;
                        }
                        Console.SetCursorPosition(Console.CursorLeft - 1, Console.CursorTop);
                        Console.Write("=" + sum);
                        break;
                    case "exit":
                        isOpen = false;
                        break;
                    default:
                        int temp = Convert.ToInt32(command);
                        int[] tempArray = new int[array.Length + 1];
                        for (int i = 0; i < array.Length; i++)
                        {
                            tempArray[i] = array[i];
                        }
                        array = tempArray;
                        array[array.Length - 1] = temp;
                        break;
                }
                Console.ReadKey();
            }
        }
    }
}