/// Write a program and ask the user to supply a list of comma separated numbers (e.g 5, 1, 9, 2, 10). If the list is 

        /// empty or includes less than 5 numbers, display "Invalid List" and ask the user to re-try; otherwise, display 

        /// the 3 smallest numbers in the list.

​

using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        string[] elements;

        while (true)

        {

            Console.WriteLine("Enter a list of comma separated numbers.");

            var input = Console.ReadLine();

            if (!String.IsNullOrEmpty(input))

            {

                elements = input.Split(',');

                if (elements.Length >= 5)

                    break;

            }

            else 

                Console.WriteLine("Invalid List. Please try again.");

        }

        var numbers = new List<int>();

        foreach (var number in elements)

        {

            numbers.Add(int.Parse(number));

        }

        var smallests = new List<int>();

        while (smallests.Count < 3)

        {

            var min = numbers[0];

            foreach (var number in numbers)

            {

            if (number < min)

                min = number;

            }

            smallests.Add(min);

            numbers.Remove(min);

        }

        Console.WriteLine("Smallest Numbers:");

        foreach (var number in smallests)

        {

            Console.WriteLine(number);

        }

    }

}

​