1. What is Objective-C?
a) A programming language
b) A design pattern
c) An operating system
d) A web framework
Answer: a) A programming language
2. Who developed Objective-C?
a) Apple Inc.
b) Microsoft
c) Google
d) Adobe Systems
Answer: a) Apple Inc.
3. What is the purpose of @synthesize in Objective-C?
a) It generates accessors for properties
b) It allocates memory for an object
c) It releases memory for an object
d) It defines an instance variable
Answer: a) It generates accessors for properties
4. What is the purpose of @property in Objective-C?
a) It declares instance variables
b) It defines methods for a class
c) It specifies the properties of a class
d) It allocates memory for objects
Answer: c) It specifies the properties of a class
5. What is the primary use of protocols in Objective-C?
a) To define a set of methods that a class should implement
b) To allocate memory for objects
c) To define instance variables
d) To create a subclass
Answer: a) To define a set of methods that a class should implement
6. How do you declare a method in Objective-C?
a) -(void)methodName;
b) (void)methodName;
c) methodName;
d) methodName();
Answer: a) -(void)methodName;
7. What is a selector in Objective-C?
a) A unique identifier for a method
b) A data type in Objective-C
c) A reserved word in Objective-C
d) A variable in Objective-C
Answer: a) A unique identifier for a method
8. How do you create a new instance of a class in Objective-C?
a) [[ClassName alloc] init];
b) [new ClassName];
c) [ClassName createInstance];
d) ClassName();
Answer: a) [[ClassName alloc] init];
9. What is the purpose of the retain count in Objective-C memory management?
a) To track the number of strong references to an object
b) To deallocate memory for an object
c) To track the number of autorelease pool releases
d) To track the number of objects in an array
Answer: a) To track the number of strong references to an object
10. What is ARC (Automatic Reference Counting) in Objective-C?
a) A technique for managing memory automatically
b) A design pattern
c) An error handling mechanism
d) A data structure in Objective-C
Answer: a) A technique for managing memory automatically
11. What is the purpose of @autoreleasepool in Objective-C?
a) To manage memory for autorelease objects
b) To declare a new class
c) To define a property
d) To create a category
Answer: a) To manage memory for autorelease objects
12. What is the difference between nonatomic and atomic in Objective-C?
a) atomic ensures thread safety, nonatomic does not
b) nonatomic ensures thread safety, atomic does not
c) They have the same behavior
d) atomic and nonatomic are not applicable to Objective-C
Answer: a) atomic ensures thread safety, nonatomic does not
13. What does the "strong" keyword indicate in Objective-C property declaration?
a) It indicates a strong (owning) reference to the object
b) It indicates a weak reference to the object
c) It indicates an assigned reference to the object
d) It indicates a copy of the object
Answer: a) It indicates a strong (owning) reference to the object
14. Which design pattern is often used in Objective-C to achieve delegation?
a) Singleton pattern
b) Observer pattern
c) Factory pattern
d) Delegate pattern
Answer: d) Delegate pattern
15. What is the difference between "copy" and "retain" in Objective-C?
a) "copy" creates a new instance, "retain" increments the retain count
b) "copy" increments the retain count, "retain" creates a new instance
c) "copy" is used for strings, "retain" is used for objects
d) "copy" and "retain" are interchangeable in Objective-C
Answer: a) "copy" creates a new instance, "retain" increments the retain count
16. What is the purpose of the @try, @catch, and @finally blocks in Objective-C?
a) To handle exceptions
b) To declare new classes
c) To define instance variables
d) To create instances of a class
Answer: a) To handle exceptions
17. What is the purpose of NSCoder in Objective-C?
a) To encode and decode objects for archiving
b) To create user interfaces
c) To manage memory
d) To handle exceptions
Answer: a) To encode and decode objects for archiving
18. What is the role of "id" data type in Objective-C?
a) It represents an object of any class
b) It represents an integer
c) It represents a float
d) It represents a character
Answer: a) It represents an object of any class
19. What is KVC (Key-Value Coding) in Objective-C?
a) A mechanism for accessing an object’s properties indirectly
b) A design pattern
c) A sorting algorithm
d) A memory management technique
Answer: a) A mechanism for accessing an object’s properties indirectly
20. What is a category in Objective-C?
a) It allows adding methods to an existing class
b) It represents a subclass
c) It represents a protocol
d) It represents an abstract class
Answer: a) It allows adding methods to an existing class
21. What is a block in Objective-C?
a) A block of code that can be executed later
b) A block of memory
c) A block of classes
d) A block of objects
Answer: a) A block of code that can be executed later
22. How do you define a block in Objective-C?
a) ^returnType blockName = ^{
b) returnType blockName = ^{
c) void blockName = ^{
d) block blockName = ^{
Answer: a) ^returnType blockName = ^{
23. Which statement is used to terminate a loop in Objective-C?
a. return
b. break
c. continue
d. exit
Answer: b. break
24. What is the purpose of using the super keyword in Objective-C?
a. To call a superclass method
b. To create a subclass
c. To define a constant
d. To allocate memory
Answer: a. To call a superclass method
25. Which data types are used to store whole numbers in Objective-C?
a. int and long
b. float and double
c. BOOL
d. NSString
Answer: a. int and long
26. What is the purpose of the atomic and nonatomic keywords in Objective-C?
a. To define constants
b. To specify the data type
c. To manage thread safety
d. To allocate memory
Answer: c. To manage thread safety
27. What is the purpose of using #import in Objective-C?
a. To include a header file
b. To define a constant
c. To import a class
d. To allocate memory
Answer: a. To include a header file
28. What is KVC (Key-Value Coding) in Objective-C?
a. A method
b. A design pattern
c. A programming paradigm
d. A mechanism for accessing an object’s properties indirectly
Answer: d. A mechanism for accessing an object’s properties indirectly
29. What is a block in Objective-C?
a. A piece of code
b. A type of loop
c. A data structure
d. A class
Answer: a. A piece of code
30. What is the purpose of using NSLog() in Objective-C?
a. To display output to the console
b. To define a method
c. To allocate memory
d. To release memory
Answer: a. To display output to the console
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