Stylistic questions on UNIX C coding.
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From: Keith Thompson on 5 Mar 2010 16:14 Andrew Poelstra <apoelstra(a)localhost.localdomain> writes: [...] > Also, the idiomatic "count up to 10" loop is: > for(i = 0; i < 10; ++i) > > while "count down to 10" is: > for(i = 10; i >= 10; ++i) I don't think that's what you meant. [...] -- Keith Thompson (The_Other_Keith) kst-u(a)mib.org <http://www.ghoti.net/~kst> Nokia "We must do something. This is something. Therefore, we must do this." -- Antony Jay and Jonathan Lynn, "Yes Minister"
From: Andrew Poelstra on 5 Mar 2010 16:27 On 2010-03-05, Keith Thompson <kst-u(a)mib.org> wrote: > Andrew Poelstra <apoelstra(a)localhost.localdomain> writes: > [...] >> Also, the idiomatic "count up to 10" loop is: >> for(i = 0; i < 10; ++i) >> >> while "count down to 10" is: >> for(i = 10; i >= 10; ++i) > > I don't think that's what you meant. > :) for(i = 10; i >= 0; ++i) vi makes copy/paste too easy to do without looking at the screen. -- Andrew Poelstra http://www.wpsoftware.net/andrew
From: Keith Thompson on 5 Mar 2010 16:38 Andrew Poelstra <apoelstra(a)localhost.localdomain> writes: > On 2010-03-05, Keith Thompson <kst-u(a)mib.org> wrote: >> Andrew Poelstra <apoelstra(a)localhost.localdomain> writes: >> [...] >>> Also, the idiomatic "count up to 10" loop is: >>> for(i = 0; i < 10; ++i) >>> >>> while "count down to 10" is: >>> for(i = 10; i >= 10; ++i) >> >> I don't think that's what you meant. >> > > :) > > for(i = 10; i >= 0; ++i) > > vi makes copy/paste too easy to do without looking at the > screen. So that's counting down *from* 10, not *to* 10 (speaking of copy/paste). Also, the "up to 10" loop executes 10 times, for values from 0 to 9 inclusive, while the "down from 10" loop executes 11 times, for values from 10 down to 0 inclusive. Finally, it's an infinite loop if i is of an unsigned type. -- Keith Thompson (The_Other_Keith) kst-u(a)mib.org <http://www.ghoti.net/~kst> Nokia "We must do something. This is something. Therefore, we must do this." -- Antony Jay and Jonathan Lynn, "Yes Minister"
From: Andrew Poelstra on 5 Mar 2010 16:53 On 2010-03-05, Keith Thompson <kst-u(a)mib.org> wrote: > Andrew Poelstra <apoelstra(a)localhost.localdomain> writes: >> On 2010-03-05, Keith Thompson <kst-u(a)mib.org> wrote: >>> Andrew Poelstra <apoelstra(a)localhost.localdomain> writes: >>> [...] >>>> Also, the idiomatic "count up to 10" loop is: >>>> for(i = 0; i < 10; ++i) >>>> >>>> while "count down to 10" is: >>>> for(i = 10; i >= 10; ++i) >>> >>> I don't think that's what you meant. >>> >> >> :) >> >> for(i = 10; i >= 0; ++i) >> >> vi makes copy/paste too easy to do without looking at the >> screen. > > So that's counting down *from* 10, not *to* 10 (speaking of > copy/paste). > > Also, the "up to 10" loop executes 10 times, for values from 0 to 9 > inclusive, while the "down from 10" loop executes 11 times, for values > from 10 down to 0 inclusive. > > Finally, it's an infinite loop if i is of an unsigned type. > Plus, I used in ++i instead of --i. My goodness. In real life I always do: i = 10; /* or max, or probably max - 1 */ while(--i) ... -- Andrew Poelstra http://www.wpsoftware.net/andrew
From: pete on 5 Mar 2010 17:02
Andrew Poelstra wrote: > > On 2010-03-05, Keith Thompson <kst-u(a)mib.org> wrote: > > Andrew Poelstra <apoelstra(a)localhost.localdomain> writes: > >> On 2010-03-05, Keith Thompson <kst-u(a)mib.org> wrote: > >>> Andrew Poelstra <apoelstra(a)localhost.localdomain> writes: > >>> [...] > >>>> Also, the idiomatic "count up to 10" loop is: > >>>> for(i = 0; i < 10; ++i) > >>>> > >>>> while "count down to 10" is: > >>>> for(i = 10; i >= 10; ++i) > >>> > >>> I don't think that's what you meant. > >>> > >> > >> :) > >> > >> for(i = 10; i >= 0; ++i) > >> > >> vi makes copy/paste too easy to do without looking at the > >> screen. > > > > So that's counting down *from* 10, not *to* 10 (speaking of > > copy/paste). > > > > Also, the "up to 10" loop executes 10 times, for values from 0 to 9 > > inclusive, while the "down from 10" loop executes 11 times, for values > > from 10 down to 0 inclusive. > > > > Finally, it's an infinite loop if i is of an unsigned type. > > > > Plus, I used in ++i instead of --i. My goodness. > > In real life I always do: > > i = 10; /* or max, or probably max - 1 */ > while(--i) > ... To count down through an array with N elements, I use size_t i = N; while (i-- != 0) { array[i]; } -- pete |