Object-oriented programming · interview question
Consider a class Order with a private field quantity. Which design choice ensures the quantity is always positive?
Multiple choiceHardchapter-3-curatedpremiumoopinvariants-and-validation
Answer and explanation
Correct answer
D. Enforce a check in the setter method
Why
Implementing a check in the setter method ensures that every time the quantity is changed, the new value is validated. This encapsulation technique secures the invariant that the quantity must always be positive by centralizing the validation logic.
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