There's a superb introductory-level article about code at Bloomberg.
Here, it's very, very, very long. 38,000 words to be more precise, so don't embark upon it lightly, but if you ever were curious about how programming works or what those overpaid idiots in my profession actually deal with, this is probably the best introduction I've ever seen, including textbooks on the subject.
It's also a good way to waste a couple of hours, even if you know something about the subject already.