As I mentioned in the first post of this series, you’re often going to hear about The Three Pillars of Object-Oriented Programming. You may also hear about The Four Pillars of Object-Oriented Programming.

And it’s not that there’s a total of seven or anything like that. Instead, it’s more about what people consider to be foundational to OOP: Are there three or four major concepts?

You can surmise from the previous article (let alone the title), I believe there are four.

Two Pillars of Object-Oriented Programming: Inheritance and Polymorphism

And in this post, I’m going to cover the final two:

  • Inheritance,
  • and Polymorphism

If you’ve done any type of object-oriented programming prior to reading this article, you’ve likely heard of at least one of these.

Regardless, let’s take a look at each of them in more detail.

Two More Pillars of OOP

Before jumping into each of these, I want to be sure that you’re caught up in what we’ve covered so far.

A Word About Analysis

I won’t belabor the point, but the whole reason I’m now talking about object-oriented fundamentals is because we’re moving into a different phase of this material. We started off covering the Analysis phase which included:

  1. Analysis, Part 1
  2. Analysis, Part 2
  3. Understanding Customer Expectations
  4. Statement of Work
  5. Terms and Conditions

Now To Development

And now we’re on to the development phase. Some may call it fundamentals (but I content you can’t do good development without the fundamentals so there’s that(.

If you’ve not read the previous post, I recommend doing so before continuing as it covers the concepts of Abstraction, Encapsulation, and how it relates to WordPress.