#334 – A Base Class Variable Can Refer to Instances of Derived Classes

A variable whose type is a particular class can refer to instances of that class or it can refer to instances of any derived classes.

Assume that we have a Dog class (base class) and a Terrier class (derived class) that inherits from Dog.  A variable of type Dog can then refer to either a Dog or a Terrier.

Dog kirby = new Dog("Kirby", 15);

// Dog variable can point to Terrier
Dog jack = new Terrier("Jack", 17, "Surly");

// Terrier variable can also point to Terrier
Terrier bubba = new Terrier("Bubba", 2, "Happy");

Notice that even though the variable jack is of type Dog, it still points to an instance of a Terrier.

Advertisements

About Sean
Software developer in the Twin Cities area, passionate about software development and sailing.

3 Responses to #334 – A Base Class Variable Can Refer to Instances of Derived Classes

  1. Pingback: #335 – Accessing a Derived Class Using a Base Class Variable « 2,000 Things You Should Know About C#

  2. Lei Yu says:

    Hi, Sean. I’m a C# learner from China, and I love your C# posts very much. I want to know whether I can translate your posts into Chinese in my blogs? Certainly, I’ll give the links of your original posts. Waiting for your Reply! Lei Yu

    • Sean says:

      Hello Lei,

      I’m okay with your translating them and reposting, as long as you clearly mention me as the author and include a link back to my blog.

      Sean

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

w

Connecting to %s

%d bloggers like this: