Operation Addition Without Modification:?

Short answer: By adding new visitors (e.g., another visitor for tax calculation or shipping fees), you can introduce new operations on the same set of elements without modifying their classes. This is the key benefit of the Visitor Pattern. Benefits of the Visitor Pattern:

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.