What is the difference between IEnumerable and IEnumerator?

Short answer: IEnumerable → Provides collection traversal capability (GetEnumerator() method). IEnumerator → Used to iterate over a collection (MoveNext(), Current, Reset()).

Real-world example (ShopNest)

Think of ShopNest’s Product, Cart, and Order classes: each object holds data + behavior, so pricing rules stay next to the data they use.

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.