Swift Interview Questions and Answers for Freshers

When preparing for a Swift Interview Questions, it is essential to be well-versed in the basics and some advanced topics of the language. Here are the top 25 questions that freshers may encounter during a Swift interview, along with their answers.

Q1. What is Swift?

Ans: Swift is a powerful and intuitive programming language for macOS, iOS, watchOS, and tvOS. It is designed to work with Apple’s Cocoa and Cocoa Touch frameworks and is highly optimized for performance.

Q2. What are the advantages of Swift over Objective-C?

Ans: Swift offers numerous advantages over Objective-C, such as better readability, easier maintenance, safer type system, less code, and improved performance.

Q3. What are Optionals in Swift?

Ans: Optionals in Swift are used to represent a value that can either exist or be nil. They are declared using the ? symbol.

Q4. What is the difference between let and var in Swift?

Ans: let is used to declare constants, which means the value cannot be changed once set. var is used to declare variables that can be modified after initial assignment.

Q5. What is the difference between nil and null?

Ans: In Swift, nil represents the absence of a value for an optional. Swift does not use null; instead, it uses nil for optionals.

Q6. What is a Tuple in Swift?

Ans: A tuple is a group of multiple values combined into a single compound value. Tuples can contain values of different types.

Q7. Explain the guard statement in Swift.

Ans: The guard statement is used for early exit from a function, loop, or condition if a certain condition is not met. It helps in improving code readability and maintainability.

Q8. What are Closures in Swift?

Ans: Closures are self-contained blocks of functionality that can be passed around and used in your code. They are similar to lambdas or anonymous functions in other programming languages.

Q9. What is the difference between map, filter, and reduce in Swift?

Ans:

1. Map transforms each element of a collection.

2. Filter returns a new collection containing only elements that satisfy a given condition.

3. Reduce combines all elements into a single value using a specified closure.

Q10. Explain the concept of Protocols in Swift.

Ans: Protocols define a blueprint of methods, properties, and other requirements for particular tasks or functionality. Classes, structs, and enums can conform to protocols to provide actual implementations.

Q11. What is a Delegate in Swift?

Ans: Delegation is a design pattern in which one object acts on behalf of, or in coordination with, another object. It is commonly used for handling events or data sharing.

Q12. How do you handle errors in Swift?

Ans: Swift provides error handling with do, try, catch, and throw keywords. Functions can throw errors, and you can handle these errors using do-catch blocks.

Q13. What is the purpose of deinit in Swift?

Ans: The deinit method is called just before an instance of a class is deallocated. It is used to perform any necessary cleanup.

Q14. What are Generics in Swift?

Ans: Generics allow you to write flexible, reusable functions and types that can work with any type. They help in reducing code duplication.

Q15. Explain the Singleton pattern in Swift.

Ans: The Singleton pattern ensures that a class has only one instance and provides a global point of access to it. It is implemented by creating a static constant for the shared instance.

Q16. What is an Enum in Swift?

Ans: An enum is a type that consists of a group of related values. It provides a way to work with those values in a type-safe manner.

Q17. What is lazy in Swift?

Ans: The lazy keyword is used to delay the initialization of a stored property until it is first accessed. It is useful for optimizing performance when the property is resource-intensive.

Q18. How do you create a Singleton in Swift?

Ans: A Singleton is created by defining a static constant instance of the class within the class itself, ensuring only one instance is created.

swift

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class MySingleton {

static let shared = MySingleton()

private init() { }

}

Q19. What is a Struct in Swift?

Ans: A struct is a value type that can contain properties and methods. Structs are passed by value, meaning a copy is created when they are assigned or passed to a function.

Q20. How do you define an extension in Swift?

Ans: Extensions add new functionality to an existing class, struct, enum, or protocol. They are defined using the extension keyword.

swift

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extension String {

func reversedString() -> String {

return String(self.reversed())

}

}

Q21. What is a Higher-Order Function in Swift?

Ans: Higher-order functions are functions that take other functions as parameters or return functions as their result. Examples include map, filter, and reduce.

Q22. Explain the Codable protocol in Swift.

Ans: The Codable protocol is a type alias for the Encodable and Decodable protocols. It allows you to easily encode and decode your custom types to and from JSON or other formats.

Q23. What is the purpose of the didSet and willSet observers?

Ans: Property observers didSet and willSet allow you to respond to changes in a property’s value. willSet is called before the value is set, and didSet is called after the value is set.

Q24. What are the differences between synchronous and asynchronous tasks?

Ans: Synchronous tasks wait until the task completes before moving on to the next task. Asynchronous tasks do not wait; they move on to the next task and complete the current task in the background.

Q25. How do you manage memory in Swift?

Ans: Swift uses Automatic Reference Counting (ARC) to manage memory. ARC automatically keeps track of references to instances and deallocates them when they are no longer needed.

These questions and answers provide a solid foundation for any fresher preparing for a Swift interview. Understanding these concepts will help you showcase your knowledge and skills effectively. Read more: Online Interview Questions