Stuart: You said: > An interface does what it says on the tin: it describes an interface that a class can then tell the world it implements. > > An abstract class provides functionality as well as an interface description. An abstract class cannot be instantiated, it can only be extended. > > The logging example given by someone earlier in this thread is the most common example given for interfaces. This is where the interface is defined as an API for others to implement and/or use which then enables users to pick and choose the combination of implementations they want to use based on their requirements without needing to change any of the code of either class. I understand the "stated" differences between abstract and interface. I can cite what the differences are, but I don't see the practical application differences. To me there is no difference between an abstract class (without method declarations) and an interface. However, I view an interface as a statement (a contract) where IF you want someone to use your code you outline the methods you require them to flesh-out in their code -- but I would like to see a simple example of that. I vaguely get the logging example given by Larry, but I'm not good at abstract thinking -- I need a concrete simple example. I tried to create a demo where I had a Toaster Class that contained breadNumber() and toastSetting() methods and then created an interface so my students could use the Toaster, but it didn't really hold up as well as I wanted. So, can anyone give me a simple example where an interface is used so I can easily explain why they are important? Thanks, tedd _____________________ tedd.sperling@xxxxxxxxx http://sperling.com -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
