using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var isEqual = String.Equals("12x","12X",System.StringComparison.CurrentCultureIgnoreCase);

        Console.WriteLine(isEqual);

        var obj1 = new MyObject();

        var obj2 = new MyObject();

        var obj3 = new MyObject();

        DoSomething(new MyObject[]{obj1,obj2,obj3});

        DoSomething((IEnumerable<MyObject>)new MyObject[]{obj1,obj2,obj3});

    }

    public class MyObject{

    }

    public static void DoSomething<T>(T arg)

   where T:class

{ // do something 

       Console.WriteLine("without IEnumerable");

   }

public static void DoSomething<T>(IEnumerable<T> enumerable)

   where T:class

{ 

       // do something 

       Console.WriteLine("with IEnumerable");

}

​

}