[Solved] Consider this code snippet: override func prepare(for segue: UIStoryboardSegue,... SettingsViewController destVC.isDarkMode = true } What will happen if the destination is not SettingsViewController? | iOS Swift

iOS Swift - Navigation

Consider this code snippet: override func prepare(for segue: UIStoryboardSegue, sender: Any?) { let destVC = segue.destination as! SettingsViewController destVC.isDarkMode = true } What will happen if the destination is not SettingsViewController?

AApp will crash at runtime due to forced cast

BData will be passed successfully

CThe code will be ignored silently

DCompile-time error occurs

Step-by-Step Solution

Solution:

Step 1: Understand forced casting with 'as!'
Forced casting assumes the type is correct; if not, it causes a runtime crash.
Step 2: Identify the consequence of wrong type
If destination is not SettingsViewController, forced cast fails and app crashes.
Final Answer:
App will crash at runtime due to forced cast -> Option A
Quick Check:
Forced cast wrong type = runtime crash [OK]

Quick Trick: Avoid forced cast unless sure of type to prevent crashes [OK]

Common Mistakes:

Assuming forced cast is safe
Expecting compile-time error instead of crash
Ignoring type mismatch risks

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More iOS Swift Quizzes

SettingsViewController destVC.isDarkMode = true } What will happen if the destination is not SettingsViewController?

Step 1: Understand forced casting with 'as!'

Step 2: Identify the consequence of wrong type

Final Answer:

Quick Check:

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