easynil coalescing
Given a non-optional `let count = 5`, what does `count ?? 0` produce?
let count = 5
let result = count ?? 0why this works
Built for Swift mastery, not memorisation.
Every question is hand-checked, every answer comes with an explanation, and your progress builds into a clear picture of where you stand.
The snippet is on the page
Every Swift question shows its code before you answer, so you are reading real Swift, not a description of it.
A written explanation, always
Once you attempt a question you get the reasoning, not just a tick. That matters most on Swift, where retain cycles and capture lists, struct versus class copying, optionals and forced unwraps, protocol witness dispatch, and actor isolation in structured concurrency.
Your weak topics, named
Progress is tracked per topic across the 51 Swift topics, so revision points at the gaps instead of the whole list.
faq
Things people ask.
How many Swift MCQs are on Journey Uncommon?
549 Swift questions right now: 60 easy, 245 medium and 244 hard. That number is read straight from the question table when this page is built, so it is never a rounded marketing figure.
Do I need an account to read the Swift questions?
No. Every Swift question, including its code snippet, its difficulty and its topic, is readable without signing in. You need a free account only to submit an answer, see which option is correct, and read the worked explanation. We keep it that way so the platform stays honest about what you actually got right.
What do Swift interviewers actually test?
Retain cycles and capture lists, struct versus class copying, optionals and forced unwraps, protocol witness dispatch, and actor isolation in structured concurrency.
Which Swift topics are covered?
51 distinct topics are tagged on the Swift questions, including weak side tables, associated types, actors and actor isolation, result builders, existential containers, retain cycles and capture lists. The topic labels come from the questions themselves, so the list matches what you will actually be asked.
Is Swift practice free?
Yes. Reading is free and unlimited. A free account unlocks answering, explanations and progress tracking. Pro (₹199 per month) adds AI explanations and AI-graded guesstimates on top; it is not needed to practise Swift MCQs.
Where is Swift used in real jobs?
iOS, iPadOS, macOS, watchOS engineering, and server-side Swift at a handful of companies.
What a Swift question here actually looks like
These are 12 of the 549 Swift questions in the library, pulled live from the question table. The snippet, the difficulty and the topic are all here. The answer options and the explanation are not. Those need a free account.
Retain cycles and capture lists, struct versus class copying, optionals and forced unwraps, protocol witness dispatch, and actor isolation in structured concurrency.
Sample Swift MCQs
easystructs vs classes
Which statement about class instances assigned to two `let` constants is correct?
class Box { var n = 0 }
let x = Box()
let y = x
y.n = 42easyif let and guard let
Can you combine an optional binding and a boolean check in one `guard`?
func check(_ n: Int?) -> String {
guard let n = n, n > 0 else { return "invalid" }
return "ok: \(n)"
}
print(check(0))easyoptionals and unwrapping
What is the result of force-unwrapping here?
let dict = ["a": 1]
let v = dict["b"]!
print(v)easystructs vs classes
A struct with a stored property is held in a `let` constant. What happens?
struct Counter { var value = 0 }
let c = Counter()
c.value = 1easyif let and guard let
What is printed by this `if let` shadowing example?
let value: Int? = 10
if let value = value {
print(value + 1)
}easyenums with associated values
Why does this enum declaration fail to compile?
enum Reading: Int {
case low(Int)
case high(Int)
}easyoptional chaining
What does calling an optional method via chaining return when the method itself returns Void?
var list: [Int]? = [1, 2, 3]
let r = list?.removeAll()
print(type(of: r))easydefer
What does the function return when called as `read("data")`?
func read(_ name: String) -> String {
var status = "opened"
defer { status = "closed" }
return status
}easyarrays dictionaries sets
What is the value of `result`?
let a: Set = [1, 2, 3]
let b: Set = [3, 4, 5]
let result = a.intersection(b)
print(result)easymap filter reduce
Given an array of optional Ints, which call produces `[1, 2, 3]` from `[1, nil, 2, nil, 3]`?
let nums: [Int?] = [1, nil, 2, nil, 3]easyarrays dictionaries sets
After this runs, what is `dict["x"]`?
var dict = ["x": 1]
dict["x", default: 0] += 10Sign in to answer
Everything above is free to read. Answering needs a free account.
We keep the correct answer, the explanation and the scoring behind sign-in so the platform stays honest, which is why the correct option and the worked explanation for every Swift question stay behind a free account. Signing in is free and takes a few seconds.
Where Swift shows up
iOS, iPadOS, macOS, watchOS engineering, and server-side Swift at a handful of companies.