Mechanical rules are never a substitute for clarity of thought.

An effective way to test code is to exercise it at its natural boundaries

Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it.

The most effective debugging tool is still careful thought, coupled with judiciously placed print statements.

Trivia rarely affect efficiency. Are all the machinations worth it, when their primary effect is to make the code less readable?

As we said in the preface to the first edition, C "wears well as one's experience with it grows." With a decade more experience, we still feel that way.

Do what you think is interesting, do something that you think is fun and worthwhile, because otherwise you won't do it well anyway.