Visitor Interface (IShoppingCartVisitor):?

Short answer: The IShoppingCartVisitor interface defines the operations that can be performed on the IShoppingCartElement objects. In this case, the visitor defines Visit(Book book) and Visit(Fruit fruit) methods for different product types. public interface IShoppingCartVisitor

Example code

{ void Visit(Book book); void Visit(Fruit fruit); }

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.