using System;

using System.Collections.Generic;

using System.Collections;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var source = new List<int> { 1, 2, 3, 4, 5, 6, 7 };

        Console.WriteLine("Before FindAll");

        var result = source.FindAll(x => {

            Console.WriteLine(x);

            return x == 1;

        });

        Console.WriteLine("After FindAll");

        Console.WriteLine("Count " + result.Count());

        Console.WriteLine("Before Where");

        var enumerable = source.Where(x => 

        {

            Console.WriteLine(x);

            return x == 1;

        });

        Console.WriteLine("After Where");

        Console.WriteLine("Before ToList");

        result = enumerable.ToList();

        Console.WriteLine("After ToList");

        Console.WriteLine("Before Nested Where");

        enumerable = source.Where(x => x == 1).Where(x => {

            Console.WriteLine(x);

            return x == 1;

        });

        Console.WriteLine("After Nested Where");

        Console.WriteLine("Before Nested Where ToList");

        result = enumerable.ToList();

        Console.WriteLine("After Nested Where ToList");

        Console.WriteLine("Begin Legacy-Like Code");

        var desiredItem = source.FindAll(x => {

            Console.WriteLine(x);

            return x > 1;

        }).FirstOrDefault(x => x == 2);

        Console.WriteLine("Desired Item " + desiredItem);       

        Console.WriteLine("End Legacy-Like Code");

        Console.WriteLine("Begin Revised Code");

        desiredItem = source.Where(x => {

            Console.WriteLine(x);

            return x > 1;

        }).FirstOrDefault(x => x == 2);     

        Console.WriteLine("Desired Item " + desiredItem);

        Console.WriteLine("End Revised Code");

    }

}