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iOS Developer Interview Questions

What is the difference between an extension and a protocol extension?

Suggested approach: Extensions add functionality to specific data types, e.g. Int. Protocol extensions add functionality to protocols, for example all kinds of integers at the same time – Int, Int8, UInt64, and so on.

For bonus points you could go on to talk about how protocol extensions enable protocol-oriented programming.

  Estimated difficulty: Intermediate

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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

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