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.

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

Trying to outsmart a compiler defeats much of the purpose of using one.

Controlling complexity is the essence of computer programming.

C is a razor-sharp tool, with which one can create an elegant and efficient program or a bloody mess.

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.)

... 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.