using System;

​

public class SubProgram

{

}

​

public class Program

{

    public static void Main()

    {

        SubProgram mini = new SubProgram();

        mini = null;

        if ( object.ReferenceEquals(mini, null))

        {

            Console.WriteLine("reference is null"); 

        }

        /*

        The code below throws an exception because it's trying to use the null reference to start the method

        if ( mini.Equals(null))

        {

            Console.WriteLine("reference is null"); 

        }

        */              

    }

}