I find it mildly disturbing that so many comments are saying "But breakpoints!" One would assume that anybody who used a debugger for more than a day knows abo

I find it mildly disturbing that so many comments are saying "But breakpoints!" One would assume that anybody who used a debugger for more than a day knows about breakpoints. TFA isn't saying you have to step through every line in a debugger. It's saying that, even if you employ your amazing debugging skill to find exactly the point you want to look at, you will only be looking at that exact point in execution, and not other points at the same time. Sure, it will be a very detailed representation of that particular point, which can be extremely handy, but sometimes you want to look at a hundred different points in execution, at once. That's when printf comes handy - you just need a large monitor (or a small font and good eyes).