Composition over Inheritance

In software development, composition and inheritance are two different approaches that can be used to reuse and organize code.

Inheritance is a way to create a new class that inherits the properties and methods of an existing class. The new class is called a subclass, and it automatically has all of the features of the existing class, as well as any additional features that are defined by the subclass.

For example, in Swift, you might create a Vehicle class that has properties and methods for things like speed, direction, and acceleration. Then, you could create subclasses of Vehicle for specific types of vehicles, like Car, Truck, and Bicycle, which would automatically have all of the features of the Vehicle class, as well as any additional specific features to those types of vehicles.

Composition, on the other hand, is a way to create new classes by combining or "composing" existing classes and other objects. In composition, a new class doesn't automatically inherit the features of the existing classes and objects that it is composed of. Instead, the new class must explicitly define how it uses the features of the existing classes and objects that it is composed of.

For example, in Swift, you might create a Vehicle class and a Engine class, each with its properties and methods. Then, you could create a Car class that is composed of a Vehicle object and an Engine object rather than being a subclass of the Vehicle class. The Car class would then define how it uses the features of the Vehicle and Engine objects that it is composed of.

In general, composition is often considered to be a better approach than inheritance for organizing and reusing code. This is because composition is more flexible and less limiting than inheritance. Composition allows you to create new classes that have exactly the features and behavior that you need, without being constrained by the inheritance hierarchy. Composition also makes it easier to change the relationships between classes, because you can simply change the composition of a class rather than needing to modify the inheritance hierarchy.

Overall, composition is an important concept in the Swift programming language, and it can be a powerful tool for organizing and reusing code in your apps. If you have any more questions about composition or other features of Swift, feel free to ask. I'm here to help!