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Swift Interview Questions

IOS swift is the latest programming language released by APPLE and is meant to be replacing the Objective-C and trying to corner the industry with this prominent programming language.

So, many people have started transitioning to Swift programming language from Objective-C or just trying to learn the swift with a Java background in order to cope up with the market requirement.

For those who are preparing for a junior developer interview, here are some questions that can be helpful for you to crack the interview and to carry on your future career in the programming industry.

Following are the list of some basic Swift interview questions and answers

1. What can you Language say about swift programming?

It is one of the programming languages and also a system creating an application for iOS and OS X.
For Cocoa and Cocoa touch, this programming language is considered to be an innovative one.

2. What are the important data types found in Objective-C?

There are four data types that the developers mostly use in Objective – C.

  • BOOL – It represents a Boolean value that is true or false.
  • NSInteger – It represents an Integer.
  • NSString – It represents a string.
  • Cgfloat – It represents a floating-point value.

3. Explain Enum?

Basically, it is a type that contains a group of various related values under the same umbrella.

4. How can you prioritize the usability of the demand Process?

  • Firstly, think like a user while designing the UX.
  • Consider all the situations that prove to be useful while promoting an App.
  • Continue to work on the utility of the App, even after the launch.

5. Explain Functions?

It lets you group a series altogether to perform a specific task.A function once created can be over and over in the code, and in case you find a repeating statement in the code, then the function can be the answer to avoid the repetition.

6. List the features of Swift Programming?

  • Variables are always initialized before use.
  • Memory is managed automatically.
  • Arrays and integers are checked for overflow.
  • Switch function can be used instead of using “if” statement.
  • It eliminates the classes that are in unsafe mode.

7. How can you write a multiple line command Swift?

The multiple line comment is written in between the symbols (/*) at the start and (*/) at the end.

8. Can you explain Regular expression and Responder chain?

Regular Expression – These are the special string patterns that describe how a search is performed through a string.

Responder Chain – It is a hierarchy of objects that obtain the opportunity to respond to the events.

9. Explain some common execution states in iOS?

The states of the common execution can be as follows:

  • Not running – This state means that there is no code that is being executed and the application is completely switched off.
  • Inactive – This state means that the application is running in the background and is not receiving any events.
  • Active – This state means that the applications are running in the background and is receiving the events.
  • Background – This state means that the application is executing the code in the background.
  • Suspended – This state means that the application is in the background and is not executing.

10. What is Dictionary in Swift?

It enables you to store the key-value pairs and access the value by providing the key.It is similar to that of the hash tables in other programming languages.

11. Explain the Adapter and Memento Pattern?

Adapter – It lets the classes with incompatible interfaces to work together and it wraps itself around the object to expose a standard interface to interact with that object.

Memento – This pattern in iOS is used as a part of state restoration.

That is this externalized state can be restored without violating any encapsulation.This pattern is especially used for the archiving in Apple.

12. Why do we use swift?

Mention the advantages?

A few of the many advantages of using swift are:

  • Optional types
  • Closures
  • Built-in error handling
  • Much faster than other languages
  • Supports pattern matching
  • Type-safe language

13. How can you define a base class in swift?

The classes are not inherited directly from the base class in the Swift programming language.The classes defined by the developer without specifying the superclass becomes the base class automatically.

14. What are the control transfer statements in swift?

The control transfer statements in swift are:

  • Continue
  • Break
  • Fallthrough
  • Return

15. What do you mean by the term “defer”?

The term “defer” is a keyword that provides a block of code that executes when the execution is leaving the current scope.

16. Can you explain any three-shift pattern matching techniques?

  • Typecasting Patterns – This pattern allows you to match or cast the types.
  • Wildcard Patterns – This pattern matches as well as ignores any kind and type of value.
  • Optional Patterns – This pattern is used to match the optional values.

17. Can you explain completion handler?

When our application is making an API call and we are supposed to update the UI to show the data from the API call, then Completion Handler becomes handy and is super convenient.

18. Distinguish between @synthesize and @dynamic in Objective –C?

  • @synthesize – It generates the getter and setter methods for the property.
  • @dynamic – It notifies the compiler that the getter and setter are implemented at some other place.

19. What do you do when you realize that your App is prone to crashing?

  • Firstly, determine the iOS version or model of the device.
  • Collect enough information to reproduce the issue.
  • If possible, acquire device logs.
  • Acquire tooling or create a unit test and begin debugging once you get the idea of the nature of the issue.

20. How can you make a property optional in Swift?

Declaring a question mark “?” in the code can make a property optional.
If a property doesn’t hold a value, then this symbol “?” helps in avoiding the runtime errors.