using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        // The Three Parts of a LINQ Query:

        //  1. Data source.

        int[] numbers = new int[7] { 0, 1, 2, 3, 4, 5, 6 };

        // 2. Query creation (LINQ Query Syntax)

        // numQuery is an IEnumerable of type int

        var numQuery =

            from num in numbers

            where (num % 2) == 0

            select num;

        // 3. Query execution.

        foreach (int num in numQuery)

        {

            Console.WriteLine("The num is: " + num);

        }   

        Console.WriteLine("-----------------------");

        // 2b. Query creation (Functional Syntax using Lambda Expressions)

        var numQuery2 = numbers.Where(num => num % 2 == 0);

        // 3b. Query execution.

        foreach (int num in numQuery2)

        {

            Console.WriteLine("The num is: " + num);

        }

        Console.WriteLine("-----------------------");

        // 2c. Query creation to an Array (Functional Syntax using Lambda Expressions)

        //  - This query is defined to return an array versus the generic IEnumerable by using ToArray()

        //  - ToList() can also be used

        int[] numQuery3 = numbers.Where(num => num % 2 == 0).ToArray();

        // 3c. Query execution

        foreach (int num in numQuery3)

        {

            Console.WriteLine("The num is: " + num);

        }

    }

}