iOS Developer Interview Questions
Why is immutability important?
Suggested approach: Immutability is baked deep into Swift, and Xcode even warns if var was used when let was possible. It’s important because it’s like a programming contract: we’re saying This Thing Should Not Change, so if we try to change it the compiler will refuse.
Estimated difficulty: Easy
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
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When using arrays, what’s the difference between
map()andcompactMap()? - What is the difference between an array and a set?
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What’s the importance of key decoding strategies when using
Codable? - What are the main differences between classes and structs in Swift?
- What are one-sided ranges and when would you use them?
