Azentech Software Solutions IOS Developer Interview Questions and Answers

Serialisation in API is the process of converting data into a format that can be easily transmitted over a network.

• Serialisation is used to convert complex data structures into a format that can be easily transmitted over a network.

• It involves converting objects or data structures into a stream of bytes that can be sent over a network.

• JSON and XML are commonly used formats for serialising data in APIs.

• Serialisation is ...read more

Codable is a protocol in Swift that allows for easy encoding and decoding of data types to and from external representations.

• Codable protocol is used to convert custom data types to and from external representations such as JSON, plist, etc.

• It requires the types to conform to Encodable and Decodable protocols.

• Codable protocol provides default implementations for encoding and decoding.

• Example: struct Person: Codable { v...read more

MVVM is an architectural design pattern that separates the user interface code from the business logic and data model.

• MVVM stands for Model-View-ViewModel

• Model represents the data and business logic

• View displays the UI elements and interacts with the user

• ViewModel acts as a mediator between the Model and View, handling user inputs and updating the Model

• MVVM helps in achieving separation of concerns and making the code ...read more

Singletons can be thread-safe, but it depends on the implementation. Proper techniques must be used to ensure safety.

• Use dispatch_once in Objective-C for thread-safe singleton creation.

• In Swift, use a static constant to ensure thread safety.

• Example in Objective-C: + (instancetype)sharedInstance { static MyClass *sharedInstance; static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{ sharedInstance = [[self a...read more

Guard let and if let are both used for optional binding in Swift, but they have different scopes and control flow behaviors.

• guard let is used for early exits; if the condition fails, it exits the current scope.

• if let allows you to safely unwrap optionals, but does not require an early exit.

• Example of guard let: guard let value = optionalValue else { return } // exits if optionalValue is nil.

• Example of if let: if let va...read more

Classes are reference types, while structs are value types in Swift.

• Classes are reference types, meaning they point to the same instance in memory when assigned to a new variable.

• Structs are value types, meaning they create a new copy when assigned to a new variable.

• Classes support inheritance, while structs do not.

• Classes can have deinitializers, while structs cannot.

• Example: class Person { var name: String } vs struc...read more

The Identifiable protocol in Swift provides a way to uniquely identify instances of a type.

• Conforms to Identifiable by implementing a 'var id: UUID { get }' property.

• Useful in SwiftUI for lists and dynamic views to track changes.

• Example: struct User: Identifiable { var id = UUID(); var name: String }

• Helps in differentiating between items in a collection.

I can join within 2 weeks of receiving an offer.

• I can start within 2 weeks of receiving an offer

• I need to give notice at my current job before starting

• I have some personal commitments that I need to wrap up before joining

Use a Set to get distinct members in array while maintaining sequence.

• Iterate through the array and add each element to a Set to automatically remove duplicates.

• Create a new array by iterating through the Set to maintain the original sequence.

diff is used to compare two collections and return the differences, while guard is used for early exit in a function if a condition is not met.

• diff is a method used in Swift to compare two collections and return the differences.

• guard is a keyword used in Swift to provide an early exit from a function if a condition is not met.

• Example: let array1 = [1, 2, 3, 4], array2 = [3, 4, 5, 6]; let result = array1.diff(array2) //...read more

GCD stands for Grand Central Dispatch, a technology used in iOS for managing concurrent operations. Multithreading is the ability of a CPU to execute multiple threads concurrently.

• GCD is used for managing tasks asynchronously and efficiently utilizing system resources.

• Multithreading allows multiple tasks to run concurrently, improving performance and responsiveness of an application.

• Example: Using GCD to download image...read more