How can you implement a notification system using polymorphism?

Short answer: Define a base Notification class or interface. Derive classes like EmailNotification, SMSNotification. abstract class Notification { public abstract void Send(string message); } class EmailNotification : Notification { public override void

Example code

Send(string msg) => Console.WriteLine("Email: " + msg); }
class SMSNotification : Notification { public override void
Send(string msg) => Console.WriteLine("SMS: " + msg); }
List<Notification> notifications = new List<Notification> { new EmailNotification(), new SMSNotification() }; foreach (var n in notifications) n.Send("Hello World!");

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.