70 Must-Know Swift Interview Questions and Answers 2024

Swift Fundamentals

1.
What is the difference between let and var in Swift?
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2.
How do you define a constant that is computed at runtime in Swift?
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3.
Can you explain the purpose of optionals in Swift?
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4.
What are tuples and how are they useful in Swift?
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5.
Describe the different collection types available in Swift.
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6.
How do you handle flow control in Swift with loops and conditions?
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7.
What are enumerations in Swift and how do they support associated values?
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8.
In Swift, how are switch statements more powerful compared to other languages?
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9.
Describe the concept of type inference in Swift.
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10.
What is type casting in Swift and how is it implemented?
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Object-Oriented Programming in Swift

11.
How do you define a class in Swift?
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12.
Explain the difference between classes and structures in Swift.
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13.
What are the key principles of inheritance in Swift?
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14.
How does Swift enable encapsulation within classes and structs?
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15.
Can Swift classes have multiple inheritance?
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16.
Describe method overloading and method overriding in Swift.
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17.
What is a convenience initializer in Swift?
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18.
How can final classes or methods be beneficial in Swift?
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Protocol-Oriented Programming

19.
Define a protocol in Swift and explain its common use cases.
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20.
How do you adopt a protocol in Swift?
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21.
Explain how extensions are used in Swift.
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22.
What are protocol extensions and how do they differ from traditional extensions?
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23.
How can protocols be used to achieve polymorphism in Swift?
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24.
Discuss the concept of protocol composition in Swift.
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25.
What are associated types in Swift protocols?
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Functional Programming Features

26.
Describe the use of closures in Swift.
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27.
How do you handle escaping and non-escaping closures in Swift?
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28.
What are higher-order functions in Swift? Give an example.
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29.
Explain how you can use map, filter, and reduce functions in Swift.
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Swift Standard Library

30.
List some commonly used algorithms provided by the Swift standard library.
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31.
How does Swift handle string manipulation within its standard library?
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32.
Describe the purpose of the Optional type in the Swift standard library.
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33.
What are the benefits of using Swift’s Array compared to NSArray in Objective-C?
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Error Handling in Swift

34.
Demonstrate how to implement error handling using do-try-catch blocks in Swift.
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35.
How can you define your own error types using enumerations in Swift?
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36.
Explain the purpose of the throws keyword in function declarations.
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65.
Can you explain different ways of propagating errors in Swift?
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Swift and Memory Management

37.
Discuss how Automatic Reference Counting (ARC) works in Swift.
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38.
How do you prevent retain cycles in Swift when using closures?
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39.
Explain the concept of weak and unowned references in Swift.
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66.
Give an example where you would use unowned instead of weak.
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Concurrency and Parallelism

40.
What is the role of Grand Central Dispatch (GCD) in Swift?
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41.
Explain dispatch queues and the concept of dispatch groups in Swift.
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42.
How has async/await simplified concurrency in Swift?
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67.
How do you synchronize access to a shared resource in Swift?
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Swift's Interoperability with Objective-C

43.
How do you use Objective-C code in a Swift project?
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44.
What is a bridging header and when do you need it?
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45.
Are there any limitations when using Objective-C APIs in Swift?
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Advanced Swift Features

46.
How do generics work in Swift?
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47.
Why would you use associated types in your protocols?
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48.
What are custom operators and how can you define them in Swift?
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49.
Explain the concept of conditional conformance in Swift.
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68.
Discuss the use and benefits of opaque return types in Swift.
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69.
How would you use property wrappers in Swift to manage access to a property?
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SwiftUI and UI Development

50.
How do you declare a user interface using SwiftUI?
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51.
What is a ViewModifier in SwiftUI and when should it be used?
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52.
Demonstrate how to handle user input like taps in SwiftUI.
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53.
Explain the concept of state management in SwiftUI.
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54.
How do you navigate between views in SwiftUI?
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55.
What is the purpose of the ObservedObject and EnvironmentObject in SwiftUI?
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56.
How does SwiftUI use declarative syntax to build user interfaces?
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Swift for Server-Side Development

57.
Name a few popular frameworks for developing server-side applications in Swift.
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58.
How does Swift Package Manager facilitate server-side Swift development?
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59.
Discuss the challenges of using Swift in a server-side environment.
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Best Practices and Design Patterns

60.
What design patterns are commonly used in Swift and why?
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61.
How can you achieve dependency injection in Swift?
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62.
Explain the Model-View-ViewModel (MVVM) pattern in the context of Swift.
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63.
What are SwiftLint and why should it be used?
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64.
Describe some best practices for managing dependencies in Swift projects.
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70.
What is the Singleton pattern and how can it be implemented in Swift?
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70 Swift interview questions

What is the difference between let and var in Swift?

How do you define a constant that is computed at runtime in Swift?

Can you explain the purpose of optionals in Swift?

What are tuples and how are they useful in Swift?

Describe the different collection types available in Swift.

How do you handle flow control in Swift with loops and conditions?

What are enumerations in Swift and how do they support associated values?

In Swift, how are switch statements more powerful compared to other languages?

Describe the concept of type inference in Swift.

What is type casting in Swift and how is it implemented?

How do you define a class in Swift?

Explain the difference between classes and structures in Swift.

What are the key principles of inheritance in Swift?

How does Swift enable encapsulation within classes and structs?

Can Swift classes have multiple inheritance?

Describe method overloading and method overriding in Swift.

What is a convenience initializer in Swift?

How can final classes or methods be beneficial in Swift?

Define a protocol in Swift and explain its common use cases.

How do you adopt a protocol in Swift?

Explain how extensions are used in Swift.

What are protocol extensions and how do they differ from traditional extensions?

How can protocols be used to achieve polymorphism in Swift?

Discuss the concept of protocol composition in Swift.

What are associated types in Swift protocols?

Describe the use of closures in Swift.

How do you handle escaping and non-escaping closures in Swift?

What are higher-order functions in Swift? Give an example.

Explain how you can use map, filter, and reduce functions in Swift.

List some commonly used algorithms provided by the Swift standard library.

How does Swift handle string manipulation within its standard library?

Describe the purpose of the Optional type in the Swift standard library.

What are the benefits of using Swift’s Array compared to NSArray in Objective-C?

Demonstrate how to implement error handling using do-try-catch blocks in Swift.

How can you define your own error types using enumerations in Swift?

Explain the purpose of the throws keyword in function declarations.

Can you explain different ways of propagating errors in Swift?

Discuss how Automatic Reference Counting (ARC) works in Swift.

How do you prevent retain cycles in Swift when using closures?

Explain the concept of weak and unowned references in Swift.

Give an example where you would use unowned instead of weak.

What is the role of Grand Central Dispatch (GCD) in Swift?

Explain dispatch queues and the concept of dispatch groups in Swift.

How has async/await simplified concurrency in Swift?

How do you synchronize access to a shared resource in Swift?

How do you use Objective-C code in a Swift project?

What is a bridging header and when do you need it?

Are there any limitations when using Objective-C APIs in Swift?

How do generics work in Swift?

Why would you use associated types in your protocols?

What are custom operators and how can you define them in Swift?

Explain the concept of conditional conformance in Swift.

Discuss the use and benefits of opaque return types in Swift.

How would you use property wrappers in Swift to manage access to a property?

How do you declare a user interface using SwiftUI?

What is a ViewModifier in SwiftUI and when should it be used?

Demonstrate how to handle user input like taps in SwiftUI.

Explain the concept of state management in SwiftUI.

How do you navigate between views in SwiftUI?

What is the purpose of the ObservedObject and EnvironmentObject in SwiftUI?

How does SwiftUI use declarative syntax to build user interfaces?

Name a few popular frameworks for developing server-side applications in Swift.

How does Swift Package Manager facilitate server-side Swift development?

Discuss the challenges of using Swift in a server-side environment.

What design patterns are commonly used in Swift and why?

How can you achieve dependency injection in Swift?

Explain the Model-View-ViewModel (MVVM) pattern in the context of Swift.

What are SwiftLint and why should it be used?

Describe some best practices for managing dependencies in Swift projects.

What is the Singleton pattern and how can it be implemented in Swift?

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What is the difference between `let` and `var` in Swift?

Describe the purpose of the `Optional` type in the Swift standard library.

Demonstrate how to implement error handling using `do-try-catch` blocks in Swift.

Explain the purpose of the `throws` keyword in function declarations.

Give an example where you would use `unowned` instead of `weak`.

What is the purpose of the `ObservedObject` and `EnvironmentObject` in SwiftUI?