bighuh

Any OOP course covers the 'reasons' for OOP (such as they are). Polymorphism, inheritance, and encapsulation. Yes, you can model much the same behavior with structs and associated functions (which is really still OOP to some extent, just without any language support), but it's quite a bit of additional work.

> We make class hierarchies in order to simplify the code by allowing different parts of it to be changed independently of each other, and to eliminate duplication (which comes to the same thing).

Yeah. Exactly. Which is why Dog extends Animal. It has a set of common features (code/behaviors, and data like number of legs, amount of fur, and so on). It is a really good analogy and a really good point to give someone an idea of why you would use inheritance. It requires absolutely no programming knowledge, and best of all, it's not difficult to imagine cases where you might actually use it. c.f. basically any game with dogs in it where they're a subclass of NPCs.

And the same for Car extends Vehicle. A vehicle can have any number of wheels and any number of doors. A car can have any number of doors but it always has 4 wheels. All cars move in approximately the same way, while vehicles can articulate or skid-steer or ...

Just because something is simplified does not mean it has no value. And just because *you* would not use these designs in *your* life does not mean others wouldn't. As TFA says: "unless they are talking about writing a clone of The Sims".