How do abstract classes help in enforcing a template method pattern?

Short answer: Abstract class defines skeleton of algorithm. Derived classes override steps without changing algorithm structure. abstract class DataProcessor {

Example code

public void Process() { ReadData(); Transform(); Save(); } protected abstract void ReadData(); protected abstract void Transform(); protected void Save() => Console.WriteLine("Data saved");
}

Real-world example (ShopNest)

Checkout calls IPaymentGateway.Charge(). Razorpay and Stripe adapters implement the same interface, so ShopNest can switch gateways without rewriting the order service.

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.