objective c - What is a Protocol?

Question

I've read the documentation but I'm still confused. Can someone please explain what a protocol is? (You could give code examples but I'm really looking for an explanation)

Answer 1

Here's a great article on it. Effectively, a protocol in Objective-C is very similar to an interface in Java or a pure virtual class in C++ (although not exactly as pure virtual classes can have data members...). It's basically a guarantee that a specific class knows how to respond to a given set of methods (messages).

Edit The original article disappeared so I have replaced it with a different tutorial.