Many of us had courses, attended lectures and speeches on programming. Many of us read (even many) programming books, and regularly read articles and blogs about programming. Have you ever thought of what should have been the first thing to learn in programming? The usual "variables, operators, data structures, classes, templates, metaprogramming, ..." or something else? I've come to the conclusion that the most important thing, the first thing to learn, the one that if you're not familiar with you shouldn't even keep studying programming, is the answer to this question: "How can I verify my code works?" . If I was a teacher, right before writing my name on the blackboard (yes, this is how I like it to imagine it), I'd write this: "How can I verify my code works?". And I'll spend the entire lesson waiting for someone to come up with a reasonable solution. If nobody goes close to it, I'd assign it as an essay for the following lesson...