On Fri, Jul 30, 2010 at 11:51 PM, Steven D'Aprano <st...@pearwood.info> wrote: > On Sat, 31 Jul 2010 01:03:27 pm David Hutto wrote: > >> This fixes the floating point 'bug' when numerator is greater than >> denominator: http://python.pastebin.com/bJ5UzsBE > > I don't mean to be disparaging ... ah hell, who am I fooling? Yes I do. > What is that mess? *wink* It works except under [3], and that's fixable. And even, I know it's a good gradumacated the eighth grade, newbie attempt.*winks* back. > > I can see at least four problems with that: > > 1. You have a function called "gcd" that doesn't calculate the gcd, but > does something else as well. That makes it a misleading name.
I still have the habit of wanting to use the functions like I would an instance of the functions. > > 2. The principles of code reuse and encapsulation suggest that each > function should (as much as possible) do one thing, and do it well. You > have a function that tries to do two or three things. You should have a > single function to calculate the gcd, and a second function to use the > gcd for reducing a fraction as needed, and potentially a third function > to report the results to the user. Then maybe I should have done a larger class of functions instead then? > > 3. Your function has a serious bug. To see it, call gcd(5, 5) and see > what it doesn't do. I'll get to it, but it seems like I had that in the original, not the revised, maybe not, but did all other test cases for it, other than that > > 4. Code duplication. Your function repeats fairly major chunks of code. > Copy-and-paste programming is one of the Deadly Sins for programmers. > The way to get rid of that is by encapsulating code in functions (see > point 1 above). I thought about putting certain print statements in a function, as well as seperating the gcd into a from fractions import *, with a different parameter for each if the returning if placed it into the called function, but it seemed a little *overkill*, when it worked well within the single function, with a few parameters placed in through an instance with input. > > > > -- > Steven D'Aprano > _______________________________________________ > Tutor maillist - tu...@python.org > To unsubscribe or change subscription options: > http://mail.python.org/mailman/listinfo/tutor > _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
