Strategy Interface:?

Short answer: The ISortStrategy interface allows any concrete sorting algorithm to be swapped in and out. The context (Sorter) doesn't need to know the specifics of the algorithm; it only knows that it can call the Sort method on any strategy that implements this interface.

Real-world example (ShopNest)

Discount rules are Strategy objects: PercentageOff, FlatOff, BuyOneGetOne—checkout picks one without a huge if/else.

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.