Objective C Test Question

What is a pointer?

• A memory address that points to a specific object
• A variable
• A class
• An object that calls other objects

Answer: A memory address that points to a specific object

If you do not declare a return type for a method definition, what is the default return type?

• id
• No return type
• *NSString

Answer: id

If a class conforms to a protocol what must it do?

• Implement all or some methods and leave the rest to be implemented by subclasses
• Implement all methods which do not have a default implementation in the protocol
• Implement all methods in the protocol, except for optional ones
• Implement all methods in the protocol without exception

Answer: Implement all methods in the protocol, except for optional ones

What is the difference between methods that begin with + and -?

• Instance methods begin with - class level methods begin with +
• + methods are public, - methods are private
• + methods are inheritable, - methods are not

Answer: Instance methods begin with - class level methods begin with +

What does an Objective-C string literal look like?

• $"foo"
• #"foo"
• @"foo"
• "foo"
• NSString("foo")

Answer: @"foo"

What is the name of the type of SQL Database that iOS Supports?

• NoSql
• MySql
• SQLite
• SQL

Answer: SQLite

ARC means?

• Time's up!
• Artificial Reference Counting
• Access Reference Collation
• Application Reference Collection
• Automatic Reference Counting
• Angular Reference Courting

Answer: Automatic Reference Counting

Where is a MKAnnotationView used?

• In a button
• On a cell
• On a table view
• On a Map View

Answer: On a Map View

Where is a MKAnnotationView used?

• In a button
• On a cell
• On a table view
• On a Map View

Answer: On a Map View

Which of the following is an object?

• NSNumber
• double
• int
• float

Answer: NSNumber

What is a delegate?

• A delegate is a variable
• A delegate holds the type of data a variable stores
• A delegate is a UIView
• A delegate allows one NSObject to send messages to another NSObject, and listen to those messages

Answer: A delegate allows one NSObject to send messages to another NSObject, and listen to those messages

If you define a new class called Foo which inherits from NSObject, how do you create a new instance of it?

• Foo *temp = new Foo();
• Foo *temp = [Foo init];
• Foo *temp = System.Create(Foo);
• Foo *temp = [[Foo alloc] init];
• Foo *temp = Make Instance of Foo;

Answer: Foo *temp = [[Foo alloc] init];

What framework does the class UIButton come from?

• Foundation
• UIKit
• CoreGraphics
• EventKit
• OpenGLES

Answer: UIKit

What does the "id" type mean?

• This is a type for strings
• This is a type for a specific object of class id
• This is the general type for any kind of object regardless of class

Answer: This is the general type for any kind of object regardless of class

Which of the following is a Singleton?

• [NSArray array]
• [NSFileManager defaultManager]

Answer: [NSFileManager defaultManager]

How do you concatenate two NSStrings *foo and NSString *bar to form a new NSString *baz?

• baz = [foo appendString: bar];
• baz = foo & bar;
• baz = foo + bar;
• baz = [foo concat: bar];
• baz = [foo stringByAppendingString: bar];

Answer: baz = [foo stringByAppendingString: bar];

To have an IOS app Screen Design we used which of the following tool?

• Instruments
• Interface Designer
• None of above
• Interface builder
• Interface Xcode

Answer: Interface builder

How do you free an object?

• free(obj)
• [obj release]
• [obj dealloc]
• [obj free]
• None of the above

Answer: [obj release]

True or False? A UIButton inherits from UIView.

• True
• False

Answer: True

How can you declare a method, that can be set as the action to be performed on various events?

• -(SEL) action:(id) event;
• - (IBAction) action:(id) sender;
• -(selector) action:(id) sender;

Answer:- (IBAction) action:(id) sender;

True or False? You can compare two strings by (string1 == string2)

• True
• False

Answer: False

What type of object is this under XCode 4.5: @[rabbit, chicken, owl]

• NSDictionary
• NSString
• NSArray
• SQLite schema

Answer: NSArray     

Developers are allowed to call [super dealloc] in ARC.

• FALSE
• TRUE

Answer: FALSE