using System;

using System.Linq;

using System.Collections.Generic;

​

static class Program

{

    public static void Main()

    {

        Test(new List<int>(Enumerable.Range(0, 10)));

        Test(new Queue<int>(Enumerable.Range(0, 10)));

        Test(Enumerable.Range(0, 10));

​

        static void Test(IEnumerable<int> source)

        {

            int iterations = 0;

            int result = source.Select(x => { iterations++; return x; }).ElementAt(5);

            Console.WriteLine($"{source}, result: {result}, Iterations: {iterations}");

        }

    }

}