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iOS Developer Interview Questions

When would you use the defer keyword in Swift?

Suggested approach: Go straight in with a clear explanation before adding more detail: this is used to delay a piece of work until a function ends, similar to how try/finally works in some other languages.

Once you've done that, be sure to give a specific example such as saving a file once everything has been written – any kind of work that absolutely must take place.

For bonus points, mention how you can defer multiple pieces of work, and they get executed in reverse as Swift unwinds the defer stack.

  Estimated difficulty: Intermediate

See the full list of iOS interview questions

Important notes

  • There are over 150 interview questions in the system. Once you've read the question and come up with a suitable answer, try reading my suggested approach and see if it helps you add more detail.
  • These questions are not designed to be hard; a good interviewer is more interested in generating discussion that lets your ability and interests shine through.
  • If you answer a question with "yes" or "no" you've missed the point – interviewers prefer you to provide reasoning, explanation, or detail, so try to elaborate with examples!
  • If you're looking for detailed technical questions about the language, you should try my Swift tests instead – there are multiple challenges that will work your brain hard.
  • For a whole series of coding challenges, I wrote the perfect book for you: Swift Coding Challenges.

Related questions

See the full list of iOS interview questions

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