A Very Basic Introduction to Inheritance - Page 5

Summary

So to sum up here is what I want to get across (not all of these points were shown in the examples):

• Inheritance is a linguistic level method of code reuse.
• Subclasses (those that extend another class via the extends key word) inherit based on access modifiers set in the parent class (the one being extended).
• Both variables and methods can be inherited.
• In actionscript (and many other object based languages) a subclass can only extend one parent class. In other words, I can't do class Son extends Father, Grandfather where Grandfather is the name of another class. Some languages do support extending more than one class and this is referred to as multiple inheritance if you want to look into it.
• Inheritance chaining is allowed so I could do Class Father extends GrandFather and then Class Son extends Father which would result in Father having the variables and methods of GrandFather and class Son having the variables and methods of both Grandfather and Father.
• Multiple classes can extend the same parent class. So Class Son extends Father and Class Daughter extends Father is fine, but note that while Son and Daughter would share (as in both have) the code inherited from Father, defining a method in Daughter does not mean it appears in Son and vice versa.

So that was a very basic introduction to inheritance. Again, much more could be, and has been, said about this topic. If you want to learn more, there are always people talking about such topics in the forums.