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

90% of the functionality delivered now is better than 100% delivered never.

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.

If you're as clever as you can be when you write it, how will you ever debug it?

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

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.