Adding New Operations Without Modifying Classes:?

Short answer: You can add new operations (like taxes or shipping costs) by simply creating new visitor classes without needing to modify the existing elements (Book, Fruit). This makes it easier to extend functionality in the future.

Real-world example (ShopNest)

Use a GoF pattern in ShopNest only when it removes duplication or makes a change safer—explain the problem it solves in the interview.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.