Top 30+ Cocoa Touch Interview Questions and Answer

Are you planning to attend a Cocoa Touch interview, and are you done knowing where to start? Well, there is a tone of questions that can arise from such an interview, and you need to be equipped or prepared for anything that will come up. How you answer the question will increase your chances of being considered for the job. As a result, we have sampled out the top 30 best and most common Cocoa Touch interview questions that you should consider.

1.    What is Cocoa?

These are object-oriented software program libraries aimed at increasing the performance of iOS and OSX applications. To develop cocoa utility, the program uses both Objective C code and ANSI C code. However, cocoa programs can be programmed using C++ codes. Cocoa has three main frameworks, i.e., foundation framework, App Kit, and Core Records framework

2.    What is an application Kit?

It’s a framework used in Cocoa touch and comprises information and objects that must be implemented to create a user-friendly interface. It controls all the facts, correctly draws displays, and communicates with handwear devices. The developer can decide the degree to which they intend to use the utility kit.

3.    Name the performance tools used in Cocoa App development.

  • Instruments: these are the devices used to display information about the CPU usage, network information, thread sports, disk facts, and memory data
  • Big-Top: this performance tool indicates graph performance traits
  • Malloc debug: it gives the developer information on how much reminiscence is assigned to exceptional features. By checking allotted reminiscence, not reference in the application, it’s the ability to identify any leaks.
  • Shark: it’s a music function that calls while at the same time graphing the reminiscence allocation
  • Quartz debug is used for debugging packages that perform heavy drawing tasks. 

4.    What Is Cocoa Touch?

It’s a User interface (UI) framework designed for iOS for iPhones, watchOS, iPad, iPod Touch, and tvOS. Using cocoa touch, developers are capable of creating a rich user experience. It permits smooth movements of visual elements where we can easily see tvOS, watchOs, and iOS technology as layers 

5.    What is Cocoa touch main features?

  • UI State Preservation
  • Auto Layout
  • Notifications Service
  • Document Picker
  • TextKit
  • AirDrop
  • Multitasking
  • AirDrop

6.    What does cocoa touch offer?

It supports event-driven behaviors that are useful in managing workspaces, windows, and applications. Windows, tablets, buttons, and other user interface objects offered by cocoa touch are among the best offers that come with Cocoa touch. In a nutshell, Cocoa supports 

  • drawing and imaging, 
  • lazy loading
  • Internationalization
  • Handles undo & redo management
  • Data exchange via Copy Paste & Drag Drop
  • content formatting & pagination
  • Audio and Video via QuickTime framework

7.    What are the important classes in Cocoa?

There are various classes in Cocoa, but the common ones include;

  • NSDate: it’s a class in Cocoa that displays dates & times in different formats
  • NSNumber: these classes are representative of objects containing doubles, integers, and floats
  • NSArray: this uses zero-based indexing for an ordered group of elements/objects
  • NSXMLParser: this kind of class is used for processing XML data

8.    8. What Is Core Data?

Core data refers to the cocoa framework used to manage persistent data and object graphs. It not only saves fetch model objects but also saves them on a persistent store. Core data is mainly ideal for the management of objects that are used in many cocoa touch projects. 

9.    Name the key cocoa touch key frameworks

  • App Kit framework
  • Foundation framework
  • Core data framework
  • PushKit Framework
  • EventKit UI Framework
  • Twitter Framework
  • Message UI Framework

10. What is the difference between Cocoa and Cocoa touch?

Cocoa is an application framework for developing applications in a Mac OS-X runtime environment. At the same time, the Cocoa touch is a framework used for developing Apple products such as the iPod touch, iPhone, and iPad. 

11. What is Xcode?

 Apple integrated development environment (IDE) for iOS and OSX is powered with XCode, which is an engine

12. How would you differentiate the mutable copy from the copy command used in Cocoa Touch?

Copy is a command used in Cocoa touch that creates an immutable copy. On the other hand, a mutable copy is a command that creates a mutable copy in cocoa touch.

13. List down the layers of Mac Osx.

Mac OSX has different layers that enable it to run efficiently, and these layers are categorized into four main groups, which include

  • User experience (UI): aqua, dashboard, accessibility, and spotlight
  • Core services: carbon core, foundation, and core foundation     
  • Application services such as media and graphics: core video, core image, OpenGL, and quartz
  • Application framework: applet, carbon, and java

14. What are the features of the foundation framework?

  • Foundation framework support object distribution and object persistence
  • It supports localization and internalization with the help of bundle technology and Unicode strings
  • It’sIt’s routed at NSobject with NSCopying protocol and NSObject

15. What is the meaning of Alloc and new as used in the cocoa torch?

Both alloc and new are used to create a new memory location, except that the new function initializes the memory location after creating it. 

16. How do you relate @property and Ivar?

iVar is an instance variable that isn’t accessible unless the developer creates assessors. These assessors are generated by @property. Both @properrty and iVar can be different. 

17. Differentiate between C/C++ and Objective C

C++

  • Both the variable and method name must be different
  • C++ compiler automatically performs name mangling
  • C++ is advantageous when it comes to referencing
  • Has static binding and strong typing, thus having templets
  • Uses static to identify factory methods amidst class methods

Objective C

  • The variable and the objects name must be similar
  • There is no reference in objective C
  • There are no templets
  • Uses – and + differentiate between class methods
  • The programmer mingles these manually

18. What is the role of the foundation kit?

The Foundation kit provides useful primitive classes and introduces paradigms that define functionalities that arena isn’t covered in objective C language. The main goals or function of the foundation kit includes;

  • Providing sets of utility classes
  • Supporting Unicode strings, object distribution, and object persistence
  • Provides OS independence, thus enhancing portability
  • Ease the software development process

19. What is the difference between Static and Dynamic Typing?

It is a type of language where the type checking is carried out during compile time. On the other hand, dynamically typed language is a type of language where type checking is carried out at runtime. Objective-C, for instance, is a dynamically typed language that doesn’t require the user to manually compile the project they are working on. 

20. Differentiate pool drain from release

Just like the name suggests, release frees the memory while drain releases NSAutoreleasePool itself

21. What do you understand by the phrases @synthesize and @property?

These are commands used in Cocoa Touch where @property declares a property and @syntheisiet creates getter & setter methods for the property declared by @property

22. What is the selector?

The selector may mean two things in Objective-C. in the first instance, and it can refer to the method name when utilized in a source code massage. On the other hand, it also means a unique identifier that substitutes the name whenever a source code is compiled. Compiled selectors are type SEL, and all methods bearing the same name 

will have a similar selector

23. What’s the difference between Immutable and Mutable?

You cannot change immutable objects, but they are used to point to a location where stored values remain constant. However, you can change the refre4nced location to another location. On the other hand, one can change the values of mutable objects. 

24. What makes category better than inheritance?

If a category is used in the cocoa touch project, then the same class can be used, and there won’t be a need to remember new class names. Furthermore, a category created on base classes will also be accessible on sub-classes.

25. What’s the meaning of a strong keyword?

Strong owns the project you are referencing with its variable or property. A compiler will ensure all the objects assigned to the property remain undestroyed, provided you point towards it using a strong reference

26. Is cocoa touch UIKit?

Mac OS-X coders use the App Kit framework that sup[plies the menus, windows, graphic contexts, event handling mechanisms, and 

buttons that define the OSX experience. Therefore, the Cocoa Touch equivalent of APPKit is known as UIKit. 

27. What is the advantage of Cocoa Touch?

  • Cocoa touch provides a user-friendly and developer-friendly interface, features that make it easier to code, create apps, and compile and run them.
  • It uses easy-to-understand and remembers objectives-C, C, and C++. 

28. Who uses cocoa touch?

It reported that almost 53 companies use cocoa touch in their tech stacks. These companies include Apple, telegram messenger, and Snapchat

29. Does SwiftUI use Cocoa Touch?

SwiftUI is considering using Cocoa touch to enable developers to create high-end apps on the Apple platform. Development has been carried out using cocoa touch and Cocoa through the APP KIT framework

30. What is a disadvantage of cocoa touch?

  • Requires one to be familiar with programming language
  • Takes time to learn, master, and know how to use the classes

Conclusion

With all the common Cocoa touch interview questions and answers listed on this page, you should be ready to face your fears. All you need is courage and master the questions and answers here; in the long run, you’ll be ahead of your competitors.  

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