On 05/30/2013 05:58 AM, Chris Angelico wrote:
On Thu, May 30, 2013 at 10:40 PM, Roy Smith <r...@panix.com> wrote:
if somebody were to accidentally drop three zeros into the source code:
x = 1000
while x < 173:
print(x)
x += 1
should the loop just quietly not execute (which is what it will do
here)? Will that make your program correct again, or will it simply
turn this into a difficult to find bug? If you're really worried about
that, why not:
If you iterate from 1000 to 173, you get nowhere. This is the expected
behaviour; this is what a C-style for loop would be written as, it's
what range() does, it's the normal thing. Going from a particular
starting point to a particular ending point that's earlier than the
start results in no iterations. The alternative would be an infinite
number of iterations, which is far far worse.
If the bug is the extra three zeros (maybe it should have been two),
then silently skipping the loop is the "far, far worse" scenario. With
the infinite loop you at least know something went wrong, and you know
it pretty darn quick (since you are testing, right? ;).
--
~Ethan~
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