Cocoa quiz

Test your Cocoa knowledge with a free interactive quiz — 24 questions with answers and explanations. No signup needed to play.

What is `NSNotificationCenter` used for?

1. What is `NSNotificationCenter` used for?
2. What is Cocoa in the context of Apple platform development?
3. What is Key-Value Coding (KVC) in Cocoa?
4. What is the purpose of `NSLayoutConstraint` and Auto Layout in Cocoa's view system?
5. What is the purpose of `NSPredicate`?
6. What does "toll-free bridging" refer to (historically, between Foundation and Core Foundation types)?
7. What role does `Info.plist` play in a Cocoa app?
8. What is a "responder chain" in Cocoa/Cocoa Touch?
9. What is the difference between Foundation and AppKit/UIKit in the Cocoa stack?
10. What is a "weak" vs a "strong" IBOutlet, and which is generally recommended for a view already retained by its superview's hierarchy?
11. What is Key-Value Observing (KVO) and how does it relate to KVC?
12. What is `NSCache` and how does it differ from a plain `NSMutableDictionary` used as a cache?

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