Objective-c - Purpose of categories and protocols

Question

I\'ve been reading up on Objective-c Protocols and Categories and both seem rather pointless to me. They\'re both used for adding things to the program in some funny way ins

Answer 1

Categories can be used to add functionality to existing classes, such as all the NS... classes. You can not add code to these directly.

Protocols are used to specify that a certain class actually does something, when you call a method in the protocol.