3.7

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace FifthProject
{
    class Program
    {
        static void Main(string[] args)
        {
            int num = 0;
            int sum = 0;
            string str;

            int[] numbers = new int[0];
            int[] tempNumbers = new int[1];

            Console.WriteLine("Введите числа: ");

            while (true)
            {
                str = Console.ReadLine();

                if (str == "sum")
                {
                    for (int i = 0; i < numbers.Length; i++)
                    {
                        sum += Convert.ToInt32(numbers[i]);
                    }
                    Console.WriteLine(sum);
                    break;
                }
                else if (str == "sort")
                {
                    int tempNum;
                    for (int i = 0; i < numbers.Length; i++)
                    {
                        for (int j = i + 1; j < numbers.Length; j++)
                        {
                            if (numbers[i] > numbers[j])
                            {
                                tempNum = numbers[i];
                                numbers[i] = numbers[j];
                                numbers[j] = tempNum;
                            }
                        }
                    }
                    for (int i = numbers.Length; i > 0; i--)
                    {
                        Console.WriteLine(numbers[i - 1]);
                    }
                    Console.ReadKey();
                    break;
                }
                else
                {
                    numbers = tempNumbers;
                    tempNumbers = new int[numbers.Length + 1];
                }

                numbers[num] = Convert.ToInt32(str);
                num++;


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