>>Gerry-
>>
>>>"Theoretically" it is possible to have bug free code. Given enough time, _anything_ is possible; eg. "Big Bang".
>>
>>Nope. Impossible to _prove_. Impossible to test in all contexts on all systems under all conditions. Even your example. However, I did qualify my comments to Jim by saying a program of sufficient complexity to be useful.
>
>I'll give you a function that's possible to prove that may look impossible. Try this (very simple)

FUNCTION AddTwo
>  LPARAMETERS tnOne, tnTwo
>
>  RETURN tnOne + tnTwo
>ENDFUNC

>> program of sufficient complexity

...and then the idea is that if you can build a whole out testable parts then you can validate the entire whole as 100% defect free. There's a couple of problems with that approach. But I think I've pretty much already made my point.

And one of them seems to have been lost. That quality does count. But "defect free" is like "mom and apple pie." *shrug*