Mid From PDF GoF Patterns Gang of Four Patterns

Concrete Observer (NewsSubscriber): ● The NewsSubscriber class represents an observer. Each subscriber has a name?

Short answer: And implements the Update() method to receive news updates from the publisher.

Explain a bit more

public class NewsSubscriber : IObserver { private readonly string _name; public NewsSubscriber(string name) => _name = name; public void Update(string news) => Console.WriteLine($"{_name} received news: {news}"); } And implements the Update() method to receive news updates from the publisher. public class NewsSubscriber : IObserver { private readonly string _name; public NewsSubscriber(string name) => _name = name;

Example code

public void Update(string news) => Console.WriteLine($"{_name} received news: {news}"); }

Real-world example (ShopNest)

When order status changes, observers update email, SMS, and analytics without the Order class knowing each one.

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.
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