Objective-C方法类型

Question

I'm just starting to teach myself objective-c and attempting to learn the cocoa touch frameworks, as like many people recently I have developed an interested in a certain little multi-touch device.

Anyway, I'm following the Stanford tutorials and I have couple of Objective-C books that im starting to make my way through. While completing one of the assignments produced by stanford, I ended up looking at the array documentation and noticed this:

Some methods have + 's and some have - 's. Whats the difference? I swear i've read what it is somewhere else before but can't for the life of me remember.

Answer 1

A minus signifies an object instance method, a plus signifies a class method - known in other languages as a ' static method '.

More info on method types can be found in this wikipedia article .