Advanced Swift Interview Questions To Hire Experienced Candidates

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.

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:
    O(1)
    O(n)
    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
    }
    createMaster()
    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
    array2.append(6)
    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")!
    printString(userPref)
    func printString(string: String) {
    println(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.