Swift Interview Questions

Swift Interview Questions

IOS swift is the latest programming language released by APPLE and is meant to be replacing the Objective-C and trying to corner the industry with this prominent programming language.

So, many people have started transitioning to Swift programming language from Objective-C or just trying to learn the swift with a Java background in order to cope up with the market requirement.

For those who are preparing for a junior developer interview, here are some questions that can be helpful for you to crack the interview and to carry on your future career in the programming industry.

Following are the list of some basic Swift interview questions and answers

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Swift Interview Questions

Declaring a question mark “?” in the code can make a property optional.
If a property doesn’t hold a value, then this symbol “?” helps in avoiding the runtime errors.

Half-Open Range Operator: It is an operator (a<b) that is used to defines a range that runs from a to b but it doesn’t contain b. The reason for its name that is half-open is that it does not contains its last value, just have its first value. The value of 'a' compulsory is not greater than b in the closed ranged operator. The resulting range will be empty in the case of a is equal to b.

It is useful when you are working with zero-based lists like arrays where it is useful to calculate the length of the list. For example:

let names = ["Alley", "Anna", "Jack", "Brian"]
let count = names.count
for i in 0..<count span id="docs-internal-guid-b356581b-7fff-3109-a868-e60b14559aae">count
print("Person \(i + 1) is called \(names[i])")
} // Person 1 is called Alley, Person 2 is called Anna, Person 3 is called Jack, Person 4 is called Brian
The states of the common execution can be as follows:
  • Not running – This state means that there is no code that is being executed and the application is completely switched off.
  • Inactive – This state means that the application is running in the background and is not receiving any events.
  • Active – This state means that the applications are running in the background and is receiving the events.
  • Background – This state means that the application is executing the code in the background.
  • Suspended – This state means that the application is in the background and is not executing.

Int (signed) and Uint (unsigned) are the two main Integer types in Swift Programming.

Basically, it is a type that contains a group of various related values under the same umbrella.
Regular Expression – These are the special string patterns that describe how a search is performed through a string.Responder Chain – It is a hierarchy of objects that obtain the opportunity to respond to the events.
It lets you group a series altogether to perform a specific task.A function once created can be over and over in the code, and in case you find a repeating statement in the code, then the function can be the answer to avoid the repetition.
It enables you to store the key-value pairs and access the value by providing the key.It is similar to that of the hash tables in other programming languages.
When our application is making an API call and we are supposed to update the UI to show the data from the API call, then Completion Handler becomes handy and is super convenient.
  • Firstly, determine the iOS version or model of the device.
  • Collect enough information to reproduce the issue.
  • If possible, acquire device logs.
  • Acquire tooling or create a unit test and begin debugging once you get the idea of the nature of the issue.

Backticks (`) are used as a name and to surround the keyword in the case if you want to give the same name as a reserved Swift keyword to a constant or a variable. But it is strongly advised to ignore the keyword unless you have no choice available.

You have to use the let keyword to declare a constant in Swift Programming. Here is the example in which we show you how to use declare street as a constant in lieu of a variable. But for this, you need to use of let keyword.

  1. let street: String = "5th Avenue"
  2. var number: Int
  3. street = "Main Street"
  4. number = 10

Swift does not allow you to change the value of constant. If you want to update the first line then XCode will show an error for a naive reason. Comment out or remove the line in which you want to change the value to the street so that it won't create any type of error.

  1. let street: String = "5th Avenue"
  2. var number: Int
  3. // street = "Main Street"
  4. number = 10
  • Firstly, think like a user while designing the UX.
  • Consider all the situations that prove to be useful while promoting an App.
  • Continue to work on the utility of the App, even after the launch.