Language Upgrades · interview question

Consider a sealed class hierarchy where you have a base class Order and two subclasses, OnlineOrder and InStoreOrder. If you add a new subclass, PhoneOrder, what change is necessary in a switch expression handling Order?

Multiple choiceHardchapter-12-curatedpremiumlanguage-upgradespattern-matching

No change is necessary as the switch will handle it automatically.Add a default case to handle PhoneOrder.Only update if PhoneOrder introduces new fields.Update the switch expression to handle PhoneOrder to ensure exhaustiveness.

Answer and explanation

Correct answer

D. Update the switch expression to handle PhoneOrder to ensure exhaustiveness.

Why

In a sealed class hierarchy, adding a new subclass requires updating the switch expression to explicitly handle the new subclass, ensuring that the code remains exhaustive and no cases are overlooked.

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Consider a sealed class hierarchy where you have a base class Order and two subclasses, OnlineOrder and InStoreOrder. If you add a new subclass, PhoneOrder, what change is necessary in a switch expression handling Order?

Correct answer

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