What are some common design patterns in C++ and their usage?

What are some common design patterns in C++ and how are they used?

Common design patterns in C++ include Singleton, Factory, Observer, and Strategy. Each serves a specific purpose.

Can you explain the Singleton pattern and give an example?

The Singleton pattern ensures a class has only one instance and provides a global point of access. For example, a logging class that should only have one instance throughout the application.

What about the Factory pattern? How does it differ from the Singleton?

The Factory pattern creates objects without specifying the exact class of object that will be created. Unlike Singleton, it can produce multiple instances of different classes.

Can you provide a code snippet for the Observer pattern?

Sure! The Observer pattern allows an object to notify other objects about changes in its state. Here's a simple example in C++.