We live in a fast food culture. Not only must our dinner arrive yesterday, our car should be fast, and our entertainment instant. Our code should also run like lightning. I want my result. And I want it now.

Ironically, writing fast programs takes a long time.

Optimisation is a spectre hanging over software development, as W.A. Wulf observed. “More computing sins are committed in the name of efficiency (without necessarily achieving it) than for any other single reason – including blind stupidity”.

It’s a well-worn subject, with plenty of trite soundbites bounding around, and the same advice being served time and time again. But despite this, a lot of code is still not developed sensibly. Programmers get sidetracked by the lure of efficiency and write bad code in the name of performance.

In these articles we’ll address this. We’ll tread some familiar ground and wander well-worn paths, but look out for some new views on the way. Don’t worry – if the subject’s optimisation it shouldn’t take too long...

No, of course not. That would make the title of this small article silly, so let’s cover two topics.

for (Surfaces::iterator sf = surfaces.begin();
     sf != surfaces.end();
     ++sf) {
  // std::cout << "Drawing: " << *sf << "\n";
  sf->draw();
}

OK, I’m being disingenuous. I’m aware that the comment isn’t really a comment, it’s commented-out code. And, like any tolerant and capable programmer, by examining the surrounding context I can guess why this code has been commented out.

This article examines how to comment out code, then describes various problems which lead to code being commented out, before finally arguing that there’s often a better solution to these problems.