[Solved] What will be the output of this code?class Cat { var age: Int init(age: Int) { self.age = age }} var cat: Cat? = nil print(cat?.age ?? -1) | Swift

Swift - Optionals

What will be the output of this code?

class Cat {
  var age: Int
  init(age: Int) { self.age = age }}

var cat: Cat? = nil
print(cat?.age ?? -1)

A-1

Bnil

C0

DRuntime error

Step-by-Step Solution

Solution:

Step 1: Understand optional chaining with nil optional
Since cat is nil, cat?.age returns nil.
Step 2: Use nil-coalescing operator
The expression cat?.age ?? -1 returns -1 because left side is nil.
Final Answer:
-1 -> Option A
Quick Check:
Nil optional with ?? returns default [OK]

Quick Trick: Use ?? to provide default when optional chaining returns nil [OK]

Common Mistakes:

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