[Solved] Given the following classes:class Address { var city: String? } class User { var... } let user = User()Which code safely prints the city name if it exists, or "Unknown" if city or address is nil? | Swift

Swift - Optionals

Given the following classes:

class Address {
  var city: String?
}
class User {
  var address: Address?
}

let user = User()

Which code safely prints the city name if it exists, or "Unknown" if city or address is nil?

Aprint(user.address.city ?? "Unknown")

Bprint(user.address?.city ?? "Unknown")

Cprint(user.address!.city!)

Dprint(user.address?.city!)

Step-by-Step Solution

Solution:

Step 1: Understand optional chaining with nil coalescing
Using user.address?.city safely accesses city, returning nil if address or city is nil.
Step 2: Use nil coalescing operator to provide default
The ?? "Unknown" provides "Unknown" if the optional is nil, avoiding crashes.
Final Answer:
print(user.address?.city ?? "Unknown") -> Option B
Quick Check:
Optional chaining + ?? = safe access with default [OK]

Quick Trick: Combine ?. with ?? to provide default value safely [OK]

Common Mistakes:

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