Objective-C quiz

Test your Objective-C knowledge with a free interactive quiz — 42 questions with answers and explanations. No signup needed to play.

What does `nil` mean in Objective-C, and what happens when you send a message to it?

1. What does `nil` mean in Objective-C, and what happens when you send a message to it?
2. What does the `id` type represent in Objective-C?
3. How do you define a constant string that is available throughout a file?
4. What happens if you forget to call `[super dealloc]` in manual reference counting (pre-ARC) code?
5. What is the delegation pattern commonly used for in Objective-C / Cocoa APIs?
6. What is the difference between `NSArray` and `NSMutableArray`?
7. What is the difference between `strong` and `weak` property attributes?
8. What does `@property (nonatomic, strong) NSString *name;` declare?
9. What are the two required file types for a typical Objective-C class?
10. What is a "selector" in Objective-C?
11. Which of these correctly declares a mutable copy of an NSString?
12. What does `@protocol` define?

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