using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        var Joe = GetNumbersFromKelly().Where(n=> n < 5); // I want all the number less than 5 and it has to look through all.

        var list = Joe.ToList(); //This will cause 

        Console.WriteLine("");

        list.ForEach(n=>Console.Write($"{n}"));

​

    }

    static IEnumerable<int> GetNumbersFromKelly()

    {

        var number = 0 ;

        while (number < 10)

        {

            Console.Write(number);

            yield return number++;

        }

    }

}