What does this code do?

Question

I'm learning c#. Most things I do understand but in this book I'm reading is this example.

abstract class GenericCustomer {
    private string name;
    public GenericCustomer() {
        name = "<no name>";
    }
    // lots of other methods
}

class Nevermore60Customer: GenericCustomer {
    private uint highCostMinutesUsed;
    // other methods etc.
}

The class is instantiated with
GenericCustomer customer = new Nevermore60Customer();

I would understand this instantiation
Nevermore60Customer customer = new Nevermore60Customer();
but I don't understand the example.

If I read it correctly it is creating an object of type GenericCustomer which is an abstract class (I didn't think you could do that) or is it a cast that creates a Nevermore60Customer but casts it as GenericCustomer (again I didn't think you could do that).

BTW I tried the code and it works. I also tried
Nevermore60Customer customer = new Nevermore60Customer();
and it works to.

Jaish Mathews · Answer

It's correct only. Here we are not creating object of GenericCustomer . But creating object of Nevermore60Customer. You can see that by just put a break point in line Nevermore60Customer customer = new Nevermore60Customer(); and on executing  customer.GetType() you can see it's Nevermore60Customer type. To avoid confusion remember like whish type has new key word that type object will be created. We have  new Nevermore60Customer();  and thay type will be created. Below another class created like class Nevermore60Customer1 : GenericCustomer { private uint highCostMinutesUsed; // other methods etc. } and object created by GenericCustomer customer1 = new Nevermore60Customer1(); Here new Nevermore60Customer1(); used. So object type is Nevermore60Customer1 You want to undeerstand that this is the purpose of abstract calss and interfaces. A common abstract type can be instantiated with different other types.