What is the difference between base reference type vs derived reference type

Question

class Dog
{
}
class BullDog : Dog
{
}
class Program
{
    static void Main()
    {
        Dog dog2 = new BullDog();
        BullDog dog3 = new BullDog();
    }
}
         


        

Answer 1

You don't need Dog dog2 = new BullDog(), you will be able to pass your BullDog to any method expecting a Dog.

Take a look at http://en.wikipedia.org/wiki/Polymorphism_in_object-oriented_programming