Dead simple OOP

Through my years of teaching, one of the most common questions I get from developers is how to best understand OOP. OOP development can seem a bit intimidating if you've never used it before. So I wanted to take a step back and give a high-level perspective of how it can be used to build applications.

My history with OOP

When I started programming over a decade ago, I learned how to build applications procedurally with languages such as C and PHP. If you're not familiar with procedural code, it simply means that you build programs in sequential order and call methods when you want shared behavior between pages in the application. For example, if I had an invoicing application, I'd have a page for creating a new invoice, another page for showing the invoice, and so on. And each page would have scripts that would call methods such as ones connecting it to the database or rendering a date in a specific format.

How does OOP work?

Now that you have a high-level view of how procedural...