Advanced Swift Interview Questions To Hire Experienced Candidates

Advanced Swift Interview Questions To Hire Experienced Candidates

RahulJune 1st, 20214 min read

Swift is a strong and automatic programming language for macOS, iOS, watchOS, tvOS, etc. Software for desktops, phones, servers, etc. are made efficiently and smoothly with the Swift programming language. Some of the characteristics of this programming language are: quick (as the name suggests!), safe, and interactive. Here, the language is optimized for development and the compiler is optimized for performance.

Swift programming language has swiftly become one of the fastest-growing languages in history. It defines broad aspects of common programming failures by utilizing advanced programming patterns such as:

  • Review array indices for out-of-bounds glitches
  • Monitor integers for overflow
  • Initialization of variables before use
  • Optional manages NIL values explicitly
  • Error handling allows controlled recovery from unexpected failures
  • Automatic memory management

Though it is simple and helpful, not everyone knows it, especially the organization’s hiring team. And, it isn’t essential!

You might want to hire a Swift developer but that does not take you to a stage where you will have to learn the applicant’s subject of interest, i.e. Swift Programming. All you need is a list of Swift interview questions. This is what you will ask your applicant.

What Should You Consider While Hiring Swift Developers?

A resume is not the only thing you will keep in mind while choosing the best fit for your team. There is more to it than just a good-looking resume. Acknowledge the following responsibilities while choosing your candidate:

  • Plan and develop applications for iOS and OS X
  • Collaborate with a team to determine, design, and direct new characteristics
  • Help maintain code quality, organization, and automatization
  • Assure the execution, excellence, and responsiveness of applications
  • Recognize and fix bottlenecks and fix bugs

Following are some of the skills to take note of:

  • Firm knowledge of object-oriented programming
  • Experience with Cocoa APIs on OS X
  • Understanding of memory management and multi-threading
  • Proficient knowledge of code versioning tools e.g. Git, Mercurial
  • Experience with continuous integration
  • Skilled in Swift, with a great understanding of its ecosystems
  • Proficiency with embedded databases and other system datastores
  • Enough sense of UI design and a user-oriented focus
  • Understanding of low-level C-based libraries is a plus
  • Implementation of computerized testing platforms and unit tests
  • Solid understanding of execution boundaries and properties
  • A knack for benchmarking and optimization
  • Experience with RESTful APIs to attach to back-end services
  • Knowledge of Apple’s design principles and interface guidelines

Besides determining the responsibilities and skills, it is essential to have the below point on your recruiting checklist.

Take A Note Of Their Technical Skills

Just by-hearting the subject’s theoretical knowledge is not enough for a good candidate. Theoretical knowledge is fine but it is not everything that you must look for in your candidate. Make sure to test his/her technical skills as well. By this, we mean testing their coding skills, practical knowledge. You need to see to it that the candidate is smart enough to implement his/her theoretical knowledge into a practical scenario.

There are so many online code editors for Swift programming language available on the web. Search for an editor that suits your expectations and make it a platform for testing your applicants.

Advanced Swift Questions You Must Ask To Hire Experienced Candidates

The technical skills of your applicant should be tracked fairly and that can be done by making him/her code on a coding interview tool and also place your interview questions before them.

Here are some of the senior Swift developer interview questions you need to have a look on:

  1. Define the significance of “?” in Swift?
  2. How to define a base class in Swift?
  3. Define Functions?
  4. How is the base class defined in Swift?
  5. What is the process to make a property optional in Swift?
  6. What is the possible approach to writing multiple-line comment swift?
  7. Tell me the various ways to unwrap an optional in swift?
  8. How to make a property optional in Swift?
  9. Define the term “defer”?
  10. What are swift messages?
  11. Consider the following code:
    let op1: Int = 1
    let op2: UInt = 2
    let op3: Double = 3.34
    var result = op1 + op2 + op3
    Where is the error and why? How can it be fixed?
  12. The String struct doesn’t provide a count or length property or method to count the number of characters it contains. Instead a global countElements<T>() function is available. When applied to strings, what’s the complexity of the countElements function:
    and why?
  13. Consider the following code:
    class Master {
    lazy var detail: Detail = Detail(master: self)
    init() {
    println("Master init")
    deinit {
    println("Master deinit")
    class Detail {
    var master: Master
    init(master: Master) {
    println("Detail init")
    self.master = master
    deinit {
    println("Detail deinit")
    func createMaster() {
    var master: Master = Master()
    var detail = master.detail
    What is the bug and how does it affect memory? How can it be fixed?
  14. Consider this code:
    let d = ["john": 23, "james": 24, "vincent": 34, "louis": 29]
    let x = d.sort{ $0.1 < $1.1 }.map{ $0.0 }

    What is the type of x? And what is its value?
  15. Explain the completion handler?
  16. Consider the following code:
    var array1 = [1, 2, 3, 4, 5]
    var array2 = array1
    var len = array1.count

    What’s the value of the len variable, and why?
  17. How to write a multiple-line comment swift?
  18. Consider the following code:
    var defaults = NSUserDefaults.standardUserDefaults()
    var userPref = defaults.stringForKey("userPref")!
    func printString(string: String) {

    Where is the bug? What does this bug cause? What’s the proper way to fix it?

These were a few advanced Swift questions that we listed for you to place in front of a senior Swift developer. As mentioned earlier, it is not mandatory for the hiring team to learn the subject but it is necessary for them to go through the answers in advance. By doing so, you will be able to ask the questions with confidence as well as be able to understand clearly what the applicant answers.

Apart from these questions, you can always rely on good live interview tools for testing your next hire. With this, we conclude this article and hope that you would be confident enough to interview your next hire now.

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