C++ Dependency Injection vs Factory Pattern

What is the difference between Dependency Injection and the Factory Pattern in C++?

Dependency Injection is a design pattern that allows a class to receive its dependencies from an external source, promoting loose coupling. The Factory Pattern, on the other hand, is used to create objects without specifying the exact class of the object that will be created.

Can you give me an example of how Dependency Injection is implemented in C++?

Sure! In C++, you can use constructor injection to pass dependencies. For example, if you have a class Car that depends on an Engine, you can inject the Engine instance through the Car constructor.

What about the Factory Pattern? How would that look in C++?

In the Factory Pattern, you would create a factory class that has a method to create objects. For instance, a CarFactory could have a method createCar() that returns a new Car object, allowing you to encapsulate the creation logic.

When should I use Dependency Injection over the Factory Pattern?

Use Dependency Injection when you want to manage dependencies externally for better testability and flexibility. Use the Factory Pattern when you need to encapsulate the creation logic of objects.