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. Brian Kernighan More Quotes by Brian Kernighan More Quotes From Brian Kernighan 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. Brian Kernighan smart inspirational funny Do what you think is interesting, do something that you think is fun and worthwhile, because otherwise you won't do it well anyway. Brian Kernighan fun interesting thinking 90% of the functionality delivered now is better than 100% delivered never. Brian Kernighan functionality Controlling complexity is the essence of computer programming. Brian Kernighan simplicity technology essence The most effective debugging tool is still careful thought, coupled with judiciously placed print statements. Brian Kernighan debugging programming tools Another effective [debugging] technique is to explain your code to someone else. This will often cause you to explain the bug to yourself. Sometimes it takes no more than a few sentences, followed by an embarrassed "Never mind, I see what's wrong. Sorry to bother you." This works remarkably well; you can even use non-programmers as listeners. One university computer center kept a teddy bear near the help desk. Students with mysterious bugs were required to explain them to the bear before they could speak to a human counselor. Brian Kernighan learning sorry mind Believe the terrain, not the map Brian Kernighan terrain maps believe C is a razor-sharp tool, with which one can create an elegant and efficient program or a bloody mess. Brian Kernighan program razors tools Each new user of a new system uncovers a new class of bugs. Brian Kernighan debugging bugs class Mechanical rules are never a substitute for clarity of thought. Brian Kernighan clarity-of-thought clarity substitutes ... it is a fundamental principle of testing that you must know in advance the answer each test case is supposed to produce. If you don't, you are not testing; you are experimenting. Brian Kernighan principles fundamentals answers Don't document bad code - rewrite it. Brian Kernighan software-engineering code-quality programming If you had done something twice, you are likely to do it again. Brian Kernighan mathematical mathematics done If you're as clever as you can be when you write it, how will you ever debug it? Brian Kernighan debugging clever writing Trivia rarely affect efficiency. Are all the machinations worth it, when their primary effect is to make the code less readable? Brian Kernighan efficiency trivia statistics Some compilers allow a check during execution that subscripts do not exceed array dimensions. This is a help, but not sufficient. First, many programmers do not use such compilers because They're not efficient. (Presumably, this means that it is vital to get the wrong answers quickly.) Brian Kernighan dimensions mean firsts An effective way to test code is to exercise it at its natural boundaries Brian Kernighan tests exercise way Trying to outsmart a compiler defeats much of the purpose of using one. Brian Kernighan defeat purpose trying Get the weirdnesses into the data where you can manipulate them easily, and the regularity into the code because regular code is a lot easier to work with Brian Kernighan weirdness easier data If you don't understand viruses, phishing, and similar threats, you become more susceptible to them. If you don't know how social networks leak information that you thought was private, you're likely to reveal much more than you realize. Brian Kernighan thought understand know you
