Skip to main content

15 Best Swift Interview Questions and Answers

What Is Swift Programming?
Swift is a powerful, open-source, safe, multi-paradigm and compiled programming language designed and developed by Chris Lattner, Apple Inc.

It is a safe, fast and interactive programming language for iOS, macOS, watchOS, tvOS and Linux.
Swift took language ideas from Objective-C, C#, Ruby, Python, Rust, Haskell, CLU and so on.
Swift Programming offers better type safety, security and performance.

Some Programming Patterns -
ü  Swift variables are always initialized before use.
ü  Swift array indices are checked for out-of-bounds errors.
ü  Swift is an alternative to the Objective-C language.
ü  Memory is managed automatically.
ü  Error handling allows controlled recovery from unexpected failures.
Swift Version History -
Mid 2010 - Development begins
Jun 2014 - Apple announces Swift at WWDC 2014
Sep 2014 - Apple releases Swift 1.0
Oct 2014 - Swift 1.1 is released
Apr2015 - Swift 1.2 is released
Mar 2017 - Apple releases Swift 3.1
June 2017 - Apple announces Swift 4.0 at WWDC 17

Is Swift Object Oriented Programming?
Yes! Swift is an Object-Oriented Programming language.

What's New Features in Swift 4.0?
ü  Faster, easier to use Strings that retain Unicode correctness
ü  Smart key paths for type-safe, efficient, extensible key value coding for Swift types
ü  Added some enhancements to creating dictionary and Set types
ü  Extends to supports of serialization to Struct
ü  Tuples and multiple return values
ü  Structs that support methods, extensions, and protocols
ü  Native error handling using try/catch/throw

What Are the Advantages of Swift?
ü  Swift is safe
ü  Swift is fast
ü  Swift is open source
ü  Swift is approachable
ü  Swift is easy to learn

What Is The Difference Between Swift And Objective-C Language?
Swift Programming-
In a swift programming, the variables and constants are declared before use.
In a swift programming, “var” keyword used for variable and “let” keyword for constant.
In a swift programming, no need to end code with semi-colon
In a swift programming, does not require creating a separate interface like Objective-C.
In a swift programming, we can define methods in class, structure or enumeration.

Objective-C Programming-
In objective-C programming, we need to end code with semi-colon
In objective-C programming, we can declare constant as int and variable as NSString.

How You define variables in Swift?
The “var” keyword is used for declaring variables and variables must be declared before they are used.
var helloMsg = "This is Anil, How Are You?"


What Is the significance of “?” in swift?
The question mark (?) is used during the declaration of a property. If the property does not hold a value, the question mark (?) helps to avoiding application errors.

Example looks like -
class Employee {
  var certificate : [Certificates]?
 }

let employee = Employee();

Example 2 -
let middleName : String? = nil
let lastName : String = "Singh"
let name : String = middleName ?? lastName


What Is Type Aliasing in Swift?
This borrows very much from C/C++. It allows us to alias a type, which can be useful in many particular contexts.
typealias sample = UInt16


What Is a deinitializer in Swift?
If you want to perform an additional clean-up of your classes, it is possible to define a block called deinit.

Syntax -
deinit {
  //Your cleanup statement here.
}


How Multiple Line Comment Can Be Written In Swift?
The Nested multiline comments enable you to comment out large blocks of code quickly and easily.
Use an opening (/*: ) and closing ( */) comment and it looks like -

/*:
     The above forward slash (/) and an asterisk (*) then a colon (:) is opening comment - (/*:)
    
     The below an asterisk (*) and forward slash is closing comment – (*))
*/

What Is difference between “let” and “var” declaration?
The “var” keyword is used for declaring variables while “let” keyword is used to declare constants.
Both variables and constants must be declared before they are used. 

Once assigned value in the constant, cannot be change but once assigned value in the variables, it can be change.
Var helloMsg = “This is Anil, How Are Yo?” // declared variable
let port = 8080; //declared  constant


How To convert NSMutableArray to Swift Array in swift?
The following code looks like -
var mutableArray = NSMutableArray(array: ["Anil", "Sunil", "Sushil"])
var swiftArray = mutableArray as NSArray as! [String]


How To convert NSArray to NSMutableArray in swift?
The following code looks like -
let array_1: NSArray = [“Anil”, “Sunil”, “Sushil”]
var mutableArray = NSMutableArray(array:array_1)

print(mutableArray)


By Anil Singh | Rating of this article (*****)

Popular posts from this blog

nullinjectorerror no provider for httpclient angular 17

In Angular 17 where the standalone true option is set by default, the app.config.ts file is generated in src/app/ and provideHttpClient(). We can be added to the list of providers in app.config.ts Step 1:   To provide HttpClient in a standalone app we could do this in the app.config.ts file, app.config.ts: import { ApplicationConfig } from '@angular/core'; import { provideRouter } from '@angular/router'; import { routes } from './app.routes'; import { provideClientHydration } from '@angular/platform-browser'; //This (provideHttpClient) will help us to resolve the issue  import {provideHttpClient} from '@angular/common/http'; export const appConfig: ApplicationConfig = {   providers: [ provideRouter(routes),  provideClientHydration(), provideHttpClient ()      ] }; The appConfig const is used in the main.ts file, see the code, main.ts : import { bootstrapApplication } from '@angular/platform-browser'; import { appConfig } from ...

How To Optimizing Database Performance: Tips and Techniques for Developers

Best Practices for Optimizing Database Performance: Tips and Techniques for Developers Navigating the labyrinth of database performance optimization can often seem like a daunting task for many professionals. Especially for database developers, mastering this critical skill has immense value, as it enhances both the efficiency and responsiveness of their applications.  Effective database performance optimization leads to faster data retrieval and smoother transactions.  A key challenge, however, lies in knowing  how to hire database developers who are well-versed in optimization techniques. The market is flooded with many professionals, but finding the right expert who understands the intricacies of database performance can be like looking for a needle in a haystack. Employers need to seek those who are not only proficient in their craft but also updated with the latest optimization practices. This guide, therefore, not only aims to provide developers with a compre...

25 Best Vue.js 2 Interview Questions and Answers

What Is Vue.js? The Vue.js is a progressive JavaScript framework and used to building the interactive user interfaces and also it’s focused on the view layer only (front end). The Vue.js is easy to integrate with other libraries and others existing projects. Vue.js is very popular for Single Page Applications developments. The Vue.js is lighter, smaller in size and so faster. It also supports the MVVM ( Model-View-ViewModel ) pattern. The Vue.js is supporting to multiple Components and libraries like - ü   Tables and data grids ü   Notifications ü   Loader ü   Calendar ü   Display time, date and age ü   Progress Bar ü   Tooltip ü   Overlay ü   Icons ü   Menu ü   Charts ü   Map ü   Pdf viewer ü   And so on The Vue.js was developed by “ Evan You ”, an Ex Google software engineer. The latest version is Vue.js 2. The Vue.js 2 is very similar to Angular because Evan ...

Top 15+ Angular 17 Interview Questions Answers | For Experienced Professionals as well

G Google team released the latest version of Angular – Angular 17 on November 6, 2023, creating a significant milestone for the super fast front-end development. What Are the New Features in Angular 17? 1.       Angular 17 is the highly anticipated release for the community, bringing many new exciting features, updates, and improvements. 2.       New Syntax for Control Flow in Templates - new @if, @switch, @for, @case, @empty @end control flow syntax 3.       Deferred Loading - @defer partial template 4.       The Angular signals API 5.       Angular SSR and client hydration 6.       Automatic Migration to Build-in Control Flow 7.       Build Performance with ESBuild 8.       By default, set this newly generated component as a standalone, and now we don't have an app module file. To use (ng...

39 Best Object Oriented JavaScript Interview Questions and Answers

Most Popular 37 Key Questions for JavaScript Interviews. What is Object in JavaScript? What is the Prototype object in JavaScript and how it is used? What is "this"? What is its value? Explain why "self" is needed instead of "this". What is a Closure and why are they so useful to us? Explain how to write class methods vs. instance methods. Can you explain the difference between == and ===? Can you explain the difference between call and apply? Explain why Asynchronous code is important in JavaScript? Can you please tell me a story about JavaScript performance problems? Tell me your JavaScript Naming Convention? How do you define a class and its constructor? What is Hoisted in JavaScript? What is function overloadin...