Interview Q&A / Object-Oriented Programming
Object-Oriented Programming interview questions
The four pillars, interfaces, abstract classes and design basics.
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- What is the difference between composition and inheritance, and when would you prefer composition?
Inheritance is an "is-a" relationship where a class extends another and reuses its code. Composition is a "has-a" relationship where a class holds other objects and delegates work to them. Prefer composition by default because it keeps classes loosely coupled and lets you swap behaviour, and use inheritance only for a true, stable "is-a" relationship.
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