At this point, I’d say that the foundations of understanding object-oriented programming have been laid.
Specifically, I’ve covered:
And, yeah, there’s some debate as to what constitutes the foundations (that is, some don’t toss polymorphism into the mix though I do). But the above four should provide a solid foundation off of which to continue building your object-oriented programming skills.
There are more, but I don’t think they are as deep, detailed, or tough to understand as some of the aforementioned concepts. Then again, different things come easier to others.
At any rate, the next two topics that are important to understand are:
I’ll talk about each separate but make sure that you’ve read the Fundamentals series first because the above two topics will allow you to rely on them and take advantage of them.
Vague, I know, but let me explain and then go from there.