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Objective-C MCQs and Answers with Explanation: Check out the Objective-C MCQ Questions and Answers available in this article to test your knowledge of Objective-C. These Objective-C Multiple Choice Questions can help you better understand the concept. Objective-C is a powerful programming language originally developed in the early 1980s as an extension of the C programming language. Due to its object-oriented programming capabilities and ability to create complex software systems for Apple’s Macintosh operating system, it quickly gained popularity among developers.
Objective C MCQ Questions and Answers
Objective-C is now widely used for developing applications for iOS and macOS, making it a valuable skill for developers in today’s tech industry. In this article, you can access the Objective C Programming Language MCQ Quiz with answers/ Objective-C Quiz to test your knowledge of this popular programming language.
Objective-C Multiple Choice Questions
| Name | Objective-C |
| Exam Type | MCQ (Multiple Choice Questions) |
| Category | Technical Quiz |
| Mode of Quiz | Online |
Top 54 Objective-C MCQ Questions with Answers | Objective-C Online Quiz
1. What is Objective C?
A) A programming language
B) An operating system
C) A software development tool
D) A hardware device
Answer: A) A programming language
Explanation: Objective-C is a programming language that is used for developing software for macOS, iOS, and other Apple platforms. It is a superset of the C programming language and adds object-oriented capabilities.
2. What is the syntax for declaring an instance variable in Objective-C?
A) int myVariable;
B) float myVariable;
C) NSString *myVariable;
D) None of the above
Answer: C) NSString *myVariable;
Explanation: In Objective-C, instance variables are declared using the syntax:
<datatype> *<variable name>;
3. Which of the following is the correct syntax for defining a method in Objective-C?
A) – (void)myMethod;
B) (void)myMethod;
C) void myMethod();
D) None of the above
Answer: A) – (void)myMethod;
Explanation: In Objective-C, methods are defined using the syntax:
(return type)method name;
4. What is the difference between a class method and an instance method in Objective-C?
A) A class method is called on an instance of a class, while an instance method is called on the class itself.
B) A class method is defined using a + symbol, while an instance method is defined using a – symbol.
C) A class method returns a value, while an instance method does not.
D) None of the above
Answer: B) A class method is defined using a + symbol, while an instance method is defined using a – symbol.
Explanation: In Objective-C, class methods are defined using a + symbol, while instance methods are defined using a – symbol. Class methods are called on the class itself, while instance methods are called on an instance of the class.
5. What is the syntax for calling a method in Objective-C?
A) myMethod();
B) [myObject myMethod];
C) myObject->myMethod();
D) None of the above
Answer: B) [myObject myMethod];
Explanation: In Objective-C, methods are called using square brackets ([]). The syntax for calling a method is:
[<object name> <method name>];
6. What is the purpose of a delegate in Objective-C?
A) To define a protocol for an object to follow
B) To provide a way for one object to communicate with another object
C) To handle memory management for an object
D) None of the above
Answer: B) To provide a way for one object to communicate with another object
Explanation: A delegate in Objective C is an object that provides a way for one object to communicate with another object. It is used to pass information between objects or to notify an object when an event occurs.
7. What is a protocol in Objective-C?
A) A set of rules that an object must follow
B) A way to define a class
C) A type of variable
D) None of the above
Answer: A) A set of rules that an object must follow
Explanation: A protocol in Objective-C is a set of rules that an object must follow in order to interact with another object. It defines a set of methods that an object must implement in order to conform to the protocol.
8. What is the difference between a category and a subclass in Objective-C?
A) A category adds methods to an existing class, while a subclass creates a new class that inherits from an existing class.
B) A category is a type of variable, while a subclass is a type of method)
C) A category is used for memory management, while a subclass is used for defining new behavior.
D) None of the above
Answer: A) A category adds methods to an existing class, while a subclass creates a new class that inherits from an existing class.
Explanation: A category in Objective-C is a way to add methods to an existing class without subclassing. It allows you to extend the functionality of an existing class. A subclass, on the other hand, creates a new class that inherits from an existing class and adds new behavior or properties to it.
9. What is ARC in Objective-C?
A) A memory management system
B) An operating system
C) A software development tool
D) A hardware device
Answer: A) A memory management system
Explanation: ARC (Automatic Reference Counting) is a memory management system used in Objective-C It automatically manages the memory of an application by tracking the number of references to an object and releasing it when it is no longer needed
10. What is the difference between strong and weak references in Objective-C?
A) A strong reference keeps an object in memory until it is explicitly released, while a weak reference does not.
B) A strong reference is used for methods, while a weak reference is used for properties.
C) A strong reference is used for properties, while a weak reference is used for methods.
D) None of the above
Answer: A) A strong reference keeps an object in memory until it is explicitly released, while a weak reference does not.
Explanation: In Objective-C, a strong reference keeps an object in memory until it is explicitly released, while a weak reference does not. A strong reference is used for objects that need to be retained for the entire lifetime of another object, while a weak reference is used for objects that may be released at any time.
11. What is a block in Objective-C?
A) A type of object
B) A way to define a function or method
C) A way to handle exceptions
D) None of the above
Answer: B) A way to define a function or method
Explanation: A block in Objective-C is a way to define a function or method inline, without having to define a separate function or method It allows you to pass code as an argument to a method or function and can be used for tasks like callbacks or enumeration.
12. What is KVC in Objective-C?
A) A programming language
B) A way to access an object’s properties using string-based keys
C) A memory management system
D) A software development tool
Answer: B) A way to access an object’s properties using string-based keys
Explanation: KVC (Key-Value Coding) is a mechanism in Objective-C that allows you to access an object’s properties using string-based keys. It provides a way to manipulate objects and their properties in a flexible and dynamic way.
13. What is KVO in Objective-C?
A) A way to observe changes to an object’s properties
B) A way to access an object’s properties using string-based keys
C) A memory management system
D) A software development tool
Answer: A) A way to observe changes to an object’s properties
Explanation: KVO (Key-Value Observing) is a mechanism in Objective-C that allows you to observe changes to an object’s properties. It provides a way to be notified when a property of an object is changed, without having to explicitly check for changes.
14. What is a category in Objective-C?
A) A way to add methods to an existing class
B) A way to define a new class
C) A type of variable
D) None of the above
Answer: A) A way to add methods to an existing class
Explanation: A category in Objective-C is a way to add methods to an existing class without subclassing. It allows you to extend the functionality of an existing class.
15. What is the difference between a property and an instance variable in Objective-C?
A) A property is a way to access an instance variable, while an instance variable is a variable that belongs to an object.
B) A property is a variable that belongs to an object, while an instance variable is a way to access a property.
C) A property and an instance variable are the same things.
D) None of the above
Answer: A) A property is a way to access an instance variable, while an instance variable is a variable that belongs to an object.
Explanation: In Objective-C, a property is a way to access an instance variable, while an instance variable is a variable that belongs to an object. The property provides a getter and setter method for accessing an instance variable, while an instance variable is accessed directly using the dot notation.
16. What is the difference between a synthesized and dynamic property in Objective-C?
A) A synthesized property is generated by the compiler, while a dynamic property is created at runtime.
B) A synthesized property is created at runtime, while a dynamic property is generated by the compiler.
C) A synthesized property is used for read-only properties, while a dynamic property is used for read-write properties.
D) None of the above
Answer: A) A synthesized property is generated by the compiler, while a dynamic property is created at runtime.
Explanation: In Objective-C, a synthesized property is generated by the compiler, while a dynamic property is created at runtime. A synthesized property creates accessor methods at compile-time, while a dynamic property creates accessor methods at runtime.
17. What is the difference between a protocol and a category in Objective-C?
A) A protocol defines a set of methods that an object can implement, while a category adds methods to an existing class.
B) A protocol adds methods to an existing class, while a category defines a set of methods that an object can implement.
C) A protocol and a category are the same things.
D) None of the above
Answer: A) A protocol defines a set of methods that an object can implement, while a category adds methods to an existing class.
Explanation: In Objective-C, a protocol defines a set of methods that an object can implement, while a category adds methods to an existing class. A protocol is used to define a set of methods that can be implemented by different classes, while a category is used to add methods to an existing class without subclassing.
18. What is the difference between a delegate and a data source in Objective-C?
A) A delegate is used for handling events, while a data source is used for providing data
B) A delegate is used for providing data, while a data source is used for handling events.
C) A delegate and a data source are the same things.
Answer: A) A delegate is used for handling events, while a data source is used for providing data
Explanation: In Objective-C, a delegate is an object that is responsible for handling events in another object. A data source is an object that provides data to another object. For example, a table view has a data source object that provides the data for the table, while a delegate object handles events such as selecting a row.
19. What is the difference between a synchronous and an asynchronous method call in Objective-C?
A) A synchronous method call blocks the calling thread until the method is complete, while an asynchronous method call does not block the calling thread
B) An asynchronous method call blocks the calling thread until the method is complete, while a synchronous method call does not block the calling thread
C) synchronous and asynchronous method calls are the same things.
D) None of the above
Answer: A) A synchronous method call blocks the calling thread until the method is complete, while an asynchronous method call does not block the calling thread
Explanation: In Objective-C, a synchronous method call blocks the calling thread until the method is complete, while an asynchronous method call does not block the calling thread) An asynchronous method call returns immediately, and the method is executed in a separate thread, while a synchronous method call waits until the method is complete before returning.
20. What is a typedef in Objective-C?
A) A typedef is used to define a new type based on an existing type.
B) A typedef is used to declare a variable.
C) A typedef is used to declare a method
D) None of the above
Answer: A) A typedef is used to define a new type based on an existing type.
Explanation: In Objective-C, a typedef is used to define a new type based on an existing type. This can make code more readable and easier to maintain, as well as make it easier to change the underlying type of a variable in the future.
21. What is an id in Objective-C?
A) An id is a pointer to an object of any type.
B) An id is a pointer to an object of a specific type.
C) An id is a pointer to a class.
D) None of the above
Answer: A) An id is a pointer to an object of any type.
Explanation: In Objective-C, an id is a pointer to an object of any type. This allows you to write generic code that can work with objects of different types.
22. What is nil in Objective-C?
A) A nil is a pointer that points to a null object.
B) A nil is a pointer that points to an object of any type.
C) A nil is a pointer that points to a class.
D) None of the above
Answer: A) A nil is a pointer that points to a null object.
Explanation: In Objective-C, nil is a pointer that points to a null object. This is used to indicate that a variable or object does not contain a valid value.
23. What is a selector in Objective-C?
A) A selector is a name that identifies a method
B) A selector is a way to declare a variable.
C) A selector is a way to declare a class.
D) None of the above
Answer: A) A selector is a name that identifies a method
Explanation: In Objective-C, a selector is a name that identifies a method A selector is used to invoke a method on an object at runtime.
24. What is a weak reference in Objective-C?
A) A weak reference is a reference to an object that does not increase the reference count of the object.
B) A weak reference is a reference to an object that increases the reference count of the object.
C) A weak reference is a reference to a class.
D) None of the above
Answer: A) A weak reference is a reference to an object that does not increase the reference count of the object.
Explanation: In Objective-C, a weak reference is a reference to an object that does not increase the reference count of the object. Weak references are often used to avoid creating a strong reference cycle between objects.
25. What is a strong reference in Objective-C?
A) A strong reference is a reference to an object that increases the reference count of the object.
B) A strong reference is a reference to an object that does not increase the reference count of the object.
C) A strong reference is a reference to a class.
D) None of the above
Answer: A) A strong reference is a reference to an object that increases the reference count of the object.
Explanation: In Objective C, a strong reference is a reference to an object that increases the reference count of the object. When an object has a strong reference, it will not be deallocated until all strong references to the object are removed
26. What is the difference between a strong and weak reference in Objective-C?
A) A strong reference increases the reference count of an object, while a weak reference does not.
B) A strong reference does not increase the reference count of an object, while a weak reference does.
C) A strong and weak reference is the same thing.
D) None of the above
Answer: A) A strong reference increases the reference count of an object, while a weak reference does not.
Explanation: In Objective-C, a strong reference increases the reference count of an object, while a weak reference does not. Strong references ensure that an object will not be deallocated until all strong references to the object are removed, while weak references are used to avoid creating a strong reference cycle between objects.
27. What is the difference between a property and a method in Objective-C?
A) A property is a way to access an instance variable, while a method is a block of code that performs a specific task
B) A property and a method are the same things.
C) A property is a block of code that performs a specific task, while a method is a way to access an instance variable.
D) None of the above
Answer: A) A property is a way to access an instance variable, while a method is a block of code that performs a specific task.
Explanation: In Objective-C, a property is a way to access an instance variable, while a method is a block of code that performs a specific task. Properties are used to encapsulate instance variables and provide a way to read and write their values. Methods, on the other hand, are used to perform specific tasks, such as updating the value of an instance variable, performing a calculation, or interacting with other objects.
28. What is the difference between a protocol and a class in Objective-C?
A) A protocol defines a set of methods that a class must implement, while a class defines a set of properties and methods.
B) A protocol defines a set of properties and methods, while a class defines a set of methods that must be implemented
C) A protocol and a class are the same things.
D) None of the above
Answer: A) A protocol defines a set of methods that a class must implement, while a class defines a set of properties and methods.
Explanation: In Objective-C, a protocol defines a set of methods that a class must implement, while a class defines a set of properties and methods. Protocols are used to define a contract between objects, specifying what messages a class can receive from another object.
29. What is the difference between an instance variable and a property in Objective-C?
A) An instance variable is a variable that is used to store data within a class, while a property is a way to access that data
B) An instance variable and a property are the same things.
C) An instance variable is a way to access data within a class, while a property is a variable that is used to store that data
D) None of the above
Answer: A) An instance variable is a variable that is used to store data within a class, while a property is a way to access that data
Explanation: In Objective-C, an instance variable is a variable that is used to store data within a class, while a property is a way to access that data Properties are used to encapsulate instance variables and provide a way to read and write their values.
30. What is the purpose of a category in Objective-C?
A) A category is a way to add methods to a class without subclassing it.
B) A category is a way to add properties to a class without subclassing it.
C) A category is a way to add both methods and properties to a class without subclassing it.
D) None of the above
Answer: A) A category is a way to add methods to a class without subclassing it.
Explanation: In Objective-C, a category is a way to add methods to a class without subclassing it. Categories are used to extend the functionality of an existing class, without modifying its implementation.
31. What is the purpose of an enumeration in Objective-C?
A) An enumeration is a way to define a set of named constants.
B) An enumeration is a way to define a set of methods.
C) An enumeration is a way to define a set of instance variables.
D) None of the above
Answer: A) An enumeration is a way to define a set of named constants.
Explanation: In Objective-C, an enumeration is a way to define a set of named constants. An enumeration is defined using the “enum” keyword and consists of a list of named constants. These named constants can then be used throughout the code to represent specific values.
32. What is the difference between retain and copy in Objective-C?
A) Retain creates a new copy of an object, while copy retains the same object.
B) Copy creates a new copy of an object, while retain retains the same object.
C) Retain and copy are the same thing.
D) None of the above
Answer: B) Copy creates a new copy of an object, while retain retains the same object.
Explanation: In Objective-C, retain is used to increment the reference count of an object, while copy creates a new copy of the object. When an object is copied, a new instance is created with the same values as the original object. When an object is retained, the reference count is incremented, indicating that another object is now holding a reference to the original object.
33. What is the difference between an abstract class and an interface in Objective-C?
A) An abstract class can have both implemented and unimplemented methods, while an interface can only have unimplemented methods.
B) An abstract class can only have unimplemented methods, while an interface can have both implemented and unimplemented methods.
C) An abstract class and an interface are the same things.
D) None of the above
Answer: A) An abstract class can have both implemented and unimplemented methods, while an interface can only have unimplemented methods.
Explanation: In Objective-C, an abstract class is a class that cannot be instantiated and contains one or more unimplemented methods that must be implemented by a subclass. An interface, on the other hand, is a set of method declarations that can be implemented by any class that conforms to that interface. Interfaces do not contain any implementation code.
34. What is the purpose of a setter method in Objective-C?
A) A setter method is used to set the value of an instance variable.
B) A setter method is used to get the value of an instance variable.
C) A setter method is used to create a new instance of a class.
D) None of the above
Answer: A) A setter method is used to set the value of an instance variable.
Explanation: In Objective-C, a setter method is used to set the value of an instance variable. Setter methods are usually defined as “set” followed by the name of the instance variable, with the first letter of the instance variable capitalized
35. What is a nil pointer in Objective-C?
A) A nil pointer is a pointer that points to a non-existent object.
B) A nil pointer is a pointer that points to an object that has been deallocated
C) A nil pointer is a pointer that points to a valid object.
D) None of the above
Answer: A) A nil pointer is a pointer that points to a non-existent object.
Explanation: In Objective-C, a nil pointer is a pointer that points to a non-existent object. A nil pointer can be used to represent the absence of an object.
36. What is the purpose of the @synthesize directive in Objective-C?
A) The @synthesize directive is used to synthesize the implementation of getter and setter methods for an instance variable.
B) The @synthesize directive is used to create a new instance of a class.
C) The @synthesize directive is used to declare a new instance variable.
D) None of the above
Answer: A) The @synthesize directive is used to synthesize the implementation of getter and setter methods for an instance variable.
Explanation: In Objective-C, the @synthesize directive is used to synthesize the implementation of getter and setter methods for an instance variable. When a property is declared using @property, the compiler automatically generates getter and setter methods for that property. The @synthesize directive is used to tell the compiler to automatically generate the implementation for those methods.
37. What is the difference between atomic and nonatomic properties in Objective-C?
A) Atomic properties ensure that access to a property is thread-safe, while nonatomic properties do not.
B) Nonatomic properties ensure that access to a property is thread-safe, while atomic properties do not.
C) Atomic and nonatomic properties are the same thing.
D) None of the above
Answer: A) Atomic properties ensure that access to a property is thread-safe, while nonatomic properties do not.
Explanation: In Objective-C, atomic properties ensure that access to a property is thread-safe, while nonatomic properties do not. Atomic properties are slower than nonatomic properties because they use locking to ensure that only one thread can access the property at a time.
38. What is the difference between a block and a function in Objective-C?
A) A block is a self-contained unit of code that can be passed around as an object, while a function is a standalone unit of code.
B) A block and a function are the same things.
C) A block is a function that returns void, while a function returns a value.
D) None of the above
Answer: A) A block is a self-contained unit of code that can be passed around as an object, while a function is a standalone unit of code.
Explanation: In Objective-C, a block is a self-contained unit of code that can be passed around as an object, while a function is a standalone unit of code. Blocks are similar to function pointers in C, but they can also capture variables from the surrounding scope.
39. What is the difference between a shallow copy and a deep copy in Objective-C?
A) A shallow copy creates a new instance of an object, while a deep copy creates a new instance of an object and also copies all of its sub-objects.
B) A deep copy creates a new instance of an object, while a shallow copy creates a new instance of an object and also copies all of its sub-objects.
C) Shallow copy and deep copy are the same things.
D) None of the above
Answer: A) A shallow copy creates a new instance of an object, while a deep copy creates a new instance of an object and also copies all of its sub-objects.
Explanation: In Objective-C, a shallow copy creates a new instance of an object, but the sub-objects are not copied Instead, the new instance and the original instance share the same sub-objects. A deep copy creates a new instance of an object and also copies all of its sub-objects, creating a completely separate copy.
40. Which of the following statements is true about protocols in Objective-C?
A) A class can implement multiple protocols.
B) A protocol can inherit from another protocol.
C) A protocol can be used to declare the methods that a class must implement.
D) All of the above
Answer: D) All of the above
Explanation: In Objective-C, a class can implement multiple protocols, a protocol can inherit from another protocol, and a protocol can be used to declare the methods that a class must implement.
41. What is the purpose of the @autoreleasepool directive in Objective-C?
A) The @autoreleasepool directive is used to create an instance of a class.
B) The @autoreleasepool directive is used to manage memory in a block of code.
C) The @autoreleasepool directive is used to declare a new instance variable.
D) None of the above
Answer: B) The @autoreleasepool directive is used to manage memory in a block of code.
Explanation: In Objective-C, the @autoreleasepool directive is used to manage memory in a block of code. When an object is created in Objective-C, it is added to an autorelease pool, which is a pool of objects that will be released at some point in the future. The @autoreleasepool directive is used to create a new autorelease pool for a block of code.
42. What is the difference between an object and a class in Objective-C?
A) An object is an instance of a class, while a class is a blueprint for creating objects.
B) An object and a class are the same things.
C) An object is a subclass of a class.
D) None of the above
Answer: A) An object is an instance of a class, while a class is a blueprint for creating objects.
Explanation: In Objective-C, an object is an instance of a class, while a class is a blueprint for creating objects. A class defines the properties and methods that an object will have, while an object is a specific instance of that class.
43. What is the purpose of the @dynamic directive in Objective-C?
A) The @dynamic directive is used to declare a dynamic property.
B) The @dynamic directive is used to generate the implementation of a property at runtime.
C) The @dynamic directive is used to declare a static property.
D) None of the above
Answer: B) The @dynamic directive is used to generate the implementation of a property at runtime.
Explanation: In Objective-C, the @dynamic directive is used to generate the implementation of a property at runtime. This is useful when you want to provide your own implementation of a property’s getter and setter methods, or when the property’s value is generated dynamically.
44. What is the purpose of the #import directive in Objective-C?
A) The #import directive is used to import a file into another file.
B) The #import directive is used to declare a new instance variable.
C) The #import directive is used to declare a new class.
D) None of the above
Answer: A) The #import directive is used to import a file into another file.
Explanation: In Objective-C, the #import directive is used to import a file into another file. This is typically used to import header files that contain the declarations of classes, methods, and other objects that are needed in the current file.
45. Which of the following statements is true about the difference between a property and an instance variable in Objective-C?
A) An instance variable is a variable that is declared in a class, while a property is a set of methods that can be used to access and modify the value of an instance variable.
B) A property is a variable that is declared in a class, while an instance variable is a set of methods that can be used to access and modify the value of a property.
C) An instance variable and a property are the same things.
D) None of the above
Answer: A) An instance variable is a variable that is declared in a class, while a property is a set of methods that can be used to access and modify the value of an instance variable.
Explanation: In Objective-C, an instance variable is a variable that is declared in a class, while a property is a set of methods that can be used to access and modify the value of an instance variable. A property provides a way to encapsulate the behavior of an instance variable and control the way it is accessed and modified
46. Which of the following statements is true about categories in Objective-C?
A) A category can be used to add methods to a class.
B) A category can be used to add instance variables to a class.
C) A category can be used to override methods in a class.
D) All of the above
Answer: A) A category can be used to add methods to a class.
Explanation: In Objective-C, a category can be used to add methods to a class, but it cannot be used to add instance variables or override existing methods. Categories provide a way to extend the functionality of a class without subclassing it.
47. What is the purpose of the #pragma directive in Objective-C?
A) The #pragma directive is used to import a file into another file.
B) The #pragma directive is used to declare a new instance variable.
C) The #pragma directive is used to control compiler options.
D) None of the above
Answer: C) The #pragma directive is used to control compiler options.
Explanation: In Objective-C, the #pragma directive is used to control compiler options. This directive can be used to control various aspects of the compilation process, such as warning messages, optimization settings, and code generation options.
48. Which of the following statements is true about blocks in Objective-C?
A) A block is a special kind of function that can be passed around like an object.
B) A block is a way to define a piece of code that can be executed at a later time.
C) A block can capture and use variables from the surrounding scope.
D) All of the above
Answer: D) All of the above
Explanation: In Objective-C, a block is a special kind of function that can be passed around like an object, can be used to define a piece of code that can be executed at a later time, and can capture and use variables from the surrounding scope. Blocks are often used for callbacks, enumerations, and other operations where a function needs to be passed as a parameter.
49. What is the purpose of the #define directive in Objective-C?
A) The #define directive is used to declare a constant value.
B) The #define directive is used to declare a new class.
C) The #define directive is used to declare a new method
D) None of the above
Answer: A) The #define directive is used to declare a constant value.
Explanation: In Objective-C, the #define directive is used to declare a constant value. This directive can be used to define constants that are used throughout a program, such as mathematical constants, error codes, or other values that are not expected to change during the execution of the program.
50. Which of the following statements is true about nil and NULL in Objective-C?
A) Nil is a pointer to an Objective-C object, while NULL is a pointer to any type of object.
B) Nil and NULL are interchangeable in Objective-C
C) Nil is used to representing a null Objective-C object pointer, while NULL is used to represent a null C pointer.
D) None of the above
Answer: C) Nil is used to representing a null Objective-C object pointer, while NULL is used to represent a null C pointer.
Explanation: In Objective-C, Nil is used to representing a null Objective-C object pointer, while NULL is used to represent a null C pointer. Nil is equivalent to (id)0, while NULL is equivalent to (void *)0. While Nil and NULL are similar, they should not be used interchangeably, as they have different meanings and can lead to errors in some situations.
51. Which of the following statements is true about dynamic binding in Objective-C?
A) Dynamic binding is the process of associating a method call with the implementation of the method in the actual class at runtime.
B) Dynamic binding is used to determine the type of an object at compile time.
C) Dynamic binding is only used for primitive data types in Objective-C
D) None of the above
Answer: A) Dynamic binding is the process of associating a method call with the implementation of the method in the actual class at runtime.
Explanation: In Objective-C, dynamic binding is the process of associating a method call with the implementation of the method in the actual class at runtime. This means that the method call is resolved at runtime, based on the type of object that is being used to make the call. This allows for greater flexibility in the design of a program, as it allows for the implementation of methods to change based on the context in which they are called
52. Which of the following statements is true about the @synthesize directive in Objective-C?
A) The @synthesize directive is used to generate getter and setter methods for a property.
B) The @synthesize directive is used to declare a new property.
C) The @synthesize directive is used to allocate memory for a new object.
D) None of the above
Answer: A) The @synthesize directive is used to generate getter and setter methods for a property.
Explanation: In Objective-C, the @synthesize directive is used to generate getter and setter methods for a property. This directive can be used to automatically generate the code for the getter and setter methods, which can save time and reduce the risk of errors in the implementation of a class.
53. What is the purpose of the retain count in Objective-C?
A) The retain count is used to keep track of the number of times an object has been retained
B) The retain count is used to determine the type of an object.
C) The retain count is used to allocate memory for a new object.
D) None of the above
Answer: A) The retain count is used to keep track of the number of times an object has been retained
Explanation: In Objective-C, the retain count is used to keep track of the number of times an object has been retained When an object is created, its retain count is set to A When another object retains the first object, the retain count is incremented by A When an object releases another object, the retain count is decremented by A When the retain count reaches 0, the object is deallocated
54. Which of the following statements is true about automatic reference counting (ARC) in Objective-C?
A) ARC is a feature that automatically manages the retain and release of objects in Objective-C
B) ARC is a feature that is only available in the latest version of Objective-C
C) ARC is a feature that is used to automatically generate code for a class.
D) None of the above
Answer: A) ARC is a feature that automatically manages the retain and release of objects in Objective-C
Explanation: Automatic reference counting (ARC) is a feature that automatically manages the retain and release of objects in Objective-C This means that developers no longer need to manually manage the retain count of objects, as the compiler automatically inserts the necessary retain and release calls. ARC is available in the latest version of Objective-C and is used to improve the memory management of Objective-C programs.
Objective-C is a powerful programming language that has played a significant role in the development of Apple’s operating systems. By testing your knowledge with these Objective C MCQ Questions and Answers, you can deepen your understanding of this language and become a more skilled iOS or macOS developer. For more technical quizzes keep checking our Freshersnow website daily.