OOP: When is it an object?

Question

I\'m trying to understand object orientation. I understand it a little bit of course, but sometimes I\'m not 100% clear. How do you decide what should be turned into an object (

Answer 1

Everything is an object. Sometimes you just use a primitive variable (int) to represent an object, and sometimes you create a data structure (struct/class). And naturally, some objects are parts of other objects.

So, yes, if you have to do in your code something with that part in the middle where you insert the key, it should also be an object in your code. It may be represented just by string Keyhole and may be represented by a class Keyhole, it may be an independent object and may be a part of the class DoorKnob - but anyway it will be an object.

In order to decide, whether an object should be independent, or should it be a part of a bigger object, you can just ask: Is it needed in the context outside the bigger object, or is it just a part of the bigger object's implementation.