Object-oriented programming

Before we start diving right into the fun of classes, let's briefly say something about object-oriented programming (OOP). OOP is a very important programming paradigm wherein code is structured in objects, leading to more maintainable and reusable code. Working with OOP teaches you to really try to think of all sorts of topics in objects, by bundling properties in such a way that they can be wrapped in a blueprint called a class. This in turn might be inheriting properties from a parent class.

For example, if we are thinking of an animal, we can come up with certain properties: name, weight, height, maximum speed, colors, and a lot more. And then if we think of a specific species of fish, we can reuse all the properties of "animal" and add a few fish-specific properties in there as well. The same for dogs; if we then think of a dog, we can reuse all the properties of "animal" and add a few dog-specific...