using System;

public class Program

{

    public static void Main()

    {   

        ParentClass parentClassInstance = new ParentClass();

        ChildClass childClassInstance = new ChildClass();

        //parentClassInstance.ProtectedVoidMethod(); //Method is inaccessible due to protection level

        //childClassInstance.ProtectedVoidMethod(); //Method is inaccessible

        //var bar = parentClassInstance.protectedObject; //Object is inaccessible

        //var foo = childClassInstance.protectedObject; //Object is inaccessible

        parentClassInstance.DoStuff();

        childClassInstance.DoStuff();

        childClassInstance.DoOtherStuff();

    }

    class ParentClass

    {

        protected object protectedObject = "RootItem";

        protected void ProtectedVoidMethod()

        {

            Console.WriteLine("ParentClass protected object: " + protectedObject.ToString());

            Console.WriteLine();

        }

        public void DoStuff()

        {           

            Console.WriteLine("ParentClass DoStuff()");

            ParentClass parentClassInstance = new ParentClass();

            parentClassInstance.ProtectedVoidMethod();

        }

    }

    class ChildClass : ParentClass

    {       

        public void DoOtherStuff()

        {

            Console.WriteLine("Child DoOtherStuff()");

            ChildClass childClassInstance = new ChildClass();

            childClassInstance.ProtectedVoidMethod(); //Child class can access protected method

            Console.WriteLine("Parent InternalClass protected object: " + this.protectedObject); //Child class can access protected member of parent class

            Console.WriteLine();

        }       

    }

}