When you are coding, to start, forget all the exceptional cases. Focus on the code for the ordinary cases first, streamlining and simplifying it, starting from the innermost loops and working out.

Then gradually add code to deal with the oddball things. If your code is clean, you will discover that there is nothing to do. The code you have written already automatically handles the weird corner cases properly. If you find yourself adding on bits of fluff to handle every special case, relook at how you coded the ordinary cases, and see if there is a way of modifying in so the odd cases come out in the wash without special coding.

Code where everything neatly comes out in the wash is:

1. easier to read and understand.
2. more likely to be bug free. Odds are it will also correctly handle other pathological conditions too that you did not think of.
3. faster.

1. It makes it clearer to the maintenance programmer which is the ordinary case and with the special.
2. The code will run slightly faster with the default fall through from the if test.

Etymology