Objective C MCQ Questions Answers

1. What is wrong with this line of code? int temp = 1==1;

2. You are worried about threaded access to a property and possible collision in writing. What directive should you use on the property?

3. What is significant about this function declaration? -(void)testFunc:(NSString**)str;

4. Dot notation can be used for _?

5. What's the difference between an array and a set?

6. What is this a declaration of? int(^foo)(int);

7. What are categories used for?

8. If you want to store a small amount of information (e.g., user settings), whats the best, built-in way to go?

9. What is an enums base type for the code below? typedef enum { Foo1, Foo2} Foo;

10. Structs can have _?

11. What is different about this function? +(void)doSomething;

12. What best describes class inheritance in Objective-C?

13. What does ARC stand for?

14. What's wrong with this code?float x = 5.;

15. What is foo? -(float)foo;

16. What is the key difference between NSDictionary and NSMutableDictionary?

17. Property defaults include _?

18. For permanent storage of some data Apple provides:

19. To display some web page, Apple provides a predefined class called:

20. What will be printed on screen after running the following code?

21. What’s the hierarchy of UITextView class until NSObject?

22. Which one is a valid property name of the NSException class?

23. If you need to raise a new exception, you will use:

24. Which of these classes are collections?

25. To create an animation, which starts slowly, but then accelerates as it progresses, you will use:

26. Which one is a valid generics type definition?

27. Which one is a valid attribute for a property declared in protocol?

28. Which of the following is true?

29. Which one is a valid property name of the NSError class?

30. Which one is an animatable property of a CALayer object?

31. A proper implementation of 'dealloc' method in your custom class must include:

32. Which statement contains a valid code for adding a method, which is not necessary to implement within a class which will conform to the protocol?

33. Correct statement for declaring a new category for UIColor class?

34. When deleting a CoreData NSManagedObject, you can specify to also delete its properties from the database, by setting a rule called:

35. Right after an exception occurs, your program executes the code from the:

36. Which statement about protocols is true?

37. Which one is NOT a predefined exception class name?

38. If there was no '@catch' block specified for handling exceptions, what will happen then?

39. Correct statement to declare a new protocol?

40. Correct code to include C 'Header.h' header in Objective-C '.m' source file?

41. Correct name of memory management method?

42. Which are valid property annotations?

43. Which of the following is true?

44. If a is an integer, the expression !a (...)?

45. As categories can't have instance variables, what class could you use to implement a full class only with categories

46. Using object-oriented programming the object that sends a message

47. All of the methods in a (...) annotated with @required must be implemented.

48. When an object's retainCount reaches 0, which message is automatically sent to that Object?

49. Considering the following Objective-c snippet, which one is NOT correct ?

50. Considering the Objective-C code, which statement is correct ?

51. Which one is a correct sample of block implementation in Objective-C?

52. It's possible to add a (...) to the standard NSString class, for example, to extend its functionality.

53. Which one is NOT correct to state about Objective-C language ?

54. if I call performSelector:withObject:afterDelay: – is the object retained ?

55. Considering best practices of memory management in Objective-C, is it correct to say that the delegate is never retained ?

56. When the above code is compiled and executed, it produces the following result:

57. The following Objective-C code defines

58. In which situation you would NOT use void types?

59. Which one is NOT correct about Protocols ?

60. The Objective-C code ... @interface MyClass : NSObject ... @end

61. Considering the following Objective-C code, what will get printed:

62. Consider below declaration of Song object and tell proper way to call name property?

63. Best way to convert NSNumber into NSString?

64. Name a property attribute that synthesizes accessors that are not thread safe?

65. Where does Objective C store objects, Heap or stack?

66. Look at below code and tell correct output?

67. What is a local variable that has no default initial value and does not retain its value through method calls?

68. Can you call C++ code from the Objective-C environment?

69. Which one is a Singleton?

70. Look at below code and provide the reference counter value after it executes:

71. What will be the output of following code?

72. Please pick the most suitable difference between alloc and dealloc?

73. An object id with a value of 0?

74. How do you search an object in an object array?

75. Property attribute that synthesizes only a getter for the property?

76. Most proper answer to load plist file contents into an array?

77. Which one contain an INCORRECT way to declare and initialize an array ?

78. In Objective-C, sometime, you may find that you wish to extend an existing class by adding behavior that is useful only in certain situations. In order to add such extension to existing classes, Objective-C provides ...

79. The (...) is an Objective-C directive, which is also used to define the aliases for various data types similar to (...). But (...) is limited to giving symbolic names to types only, whereas (...) can be used to define alias for values as well, like you can define 1 as ONE, etc.

80. Which one contains an INCORRECT concept regarding Objective-C programming ?

81. Which one is NOT correct regarding memory management in Objective-C ?

82. Memory management is one of the most important processes in any programming language

83. In Objective-C, retain counts are the way in which memory is managed.

84. Objective-C allows you to define protocols, which declare the methods expected to be used for a particular situation.

85. The description above is essentially related to which feature of Objective-C programming language ?

86. Which one is the base class of all objects in Objective-c ?

87. Which method creates and returns an NSNumber object containing a given value, treating it as an NSInteger.

88. While calling a function by reference, it will copy the actual value of an argument into the formal parameter of the function. In this case, changes made to the parameter inside the function have no effect on the argument. Is the statement above True ?

89. Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the (...) programming language

90. What happens when the following code executes?

91. Which one is correct (legal) floating-point literal ?

92. A derived class can access all the private members of its base class if it's defined in the interface class

93. In Objective-C, retain counts are the way in which memory is managed in Objective-C

94. The (...) method can be used to see if an object belongs to a class that implements a particular protocol.

95. (...) is an abstractClass which represents a stream of data. They are used in Archiving and Unarchiving objects. (...) objects are usually used in a method that is being implemented so that the class conforms to the protocol.

96. In Objective-C programming, error handling is provided with (...) class available in Foundation framework.

97. Two distinct types of problems can arise while an iOS or OS X application is running.

98. Exceptions can be handled using the standard a common pattern found in most other high-level programming languages

99. Which one is not a property of NSError class?

100. A category is a group of related methods for a class, and all of the methods defined in a category are available through the class as if they were defined in the main interface file.