Linear Data Structures ex1

namespace LinearDataStructures
{
    using System;
    using System.Collections.Generic;
    using System.Linq;

    class ListNumbers
    {
        static void Main()
        {
            Console.WriteLine("Enter some positive numbers: ");
            string input = Console.ReadLine();
            if (string.IsNullOrEmpty(input))
            {
                return;
            }

            List<int> numbers = new List<int>();

            while (!string.IsNullOrEmpty(input))
            {
                int num;
                if (int.TryParse(input, out num))
                {
                    if (num < 0)
                    {
                        throw new ArgumentException("We take only positive numbers!");
                    }

                    numbers.Add(num);
                }
                else
                {
                    throw new ArgumentException("Enter only positive numbers!");
                }

                input = Console.ReadLine();
            }

            decimal sum = numbers.Sum();

            Console.WriteLine("The sum is: {0}", sum);

            var average = numbers.Average();
            Console.WriteLine("the average is : {0}", average);
        }
    }
}