Curated iOS Interview Questions Series — Part 3

Rahul Goel
3 min readOct 6, 2021


Series aiming to cover as many Q&A’s as possible from iOS interview perspective.

Do check out Part-1, Part-2 before proceeding further.

Q 35. Is there any difference between nil and .none


Output : are same

Q36. What is the output in Playground?


Output : Welcome to Mars

The capture list creates a copy of thing when you declare the closure and does not change afterwards.

Q37. What is the output in Playground?


Output : Welcome to Earth

As the compiler would use reference, thus would use the last updated value from thing.

Q38. Recursive enumeration in Swift?

If any case in the enum contains one or more associated value as another instance of the same enum itself then it is recursive enumeration.


use indirect keyword for the same.

Q39. Can enum have stored properties and methods?


Stored Property — No


method — Yes

Q40. opaque return type in Swift?

A function or method with an opaque return type hides its return value’s type information. Instead of providing a concrete type as the function’s return type, the return value is described in terms of the protocols it supports.

Q41. What is output ?

Answer : 5, Optional(25)

Q42. What is Output?

Output : Compilation Error, Can not assign a property: ‘name’ is get only property

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Rahul Goel

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