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| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Program to count words, issues with an if condition within a for loop |
| Date | 2015-10-11 16:05 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <87egh1fntk.fsf@bsb.me.uk> (permalink) |
| References | (6 earlier) <9bf9dec8-9dad-4efc-9337-d5d8f8aca26b@googlegroups.com> <5619b89c$0$3856$426a74cc@news.free.fr> <1be5c97d-c2a4-4d21-b695-41b3b8799a76@googlegroups.com> <87wputg1ts.fsf@bsb.me.uk> <4a8e7e6d-a1c5-4479-b850-7d19ab918e50@googlegroups.com> |
Malcolm McLean <malcolm.mclean5@btinternet.com> writes:
> On Sunday, October 11, 2015 at 11:02:55 AM UTC+1, Ben Bacarisse wrote:
>> Malcolm McLean <malcolm.mclean5@btinternet.com> writes:
>> <snip>
>> >> On 10/11/15 02:56, Malcolm McLean wrote:
>> >> > But it's not always sensible to write code as lots of little
>> >> > functions.
>> >> > A major problem is "Russian doll" programming, where one user-defined
>> >> > function just calls another and another, doing trivial processing.
>> >> > Since the functions are user-defined, it's not clear what they
>> >> > actually do, and the reader is hopping about in the source, not
>> >> > getting any real answers.
>> <snip>
>> > And, as you say, the Russian doll problem doesn't apply. If you
>> > need to understand code, and you see return sqrt(a.x *b.x + a.y *b.y)
>> > you know that you've got a dot product.
>> >
>> > Similarly dot(&a, &b) is pretty harmless, as is length(&a). However
>> > when we get to anglebetween(Point2D &a, Point2D &b), the issue starts.
>> > Firstly, the angle between is defined for three points, not two,
>> > so pretty obviously we've been sloppy in the point / vector distinction.
>> > Secondly, are we looking for the signed angle, or the unsigned,
>> > the smaller or the clockwise / anticlockwise rotation from a to b?
>> > What does the function return if a or b are degenerate?
>> >
>> > Now we're in this position
>> >
>> > Point2D a = bullet.heading;
>> > Point2D b = spaceship.heading;
>> > theta = anglebetween(&a, &b);
>> > Matrix2D mtx = rotationmatrix(theta);
>> > for(i=0;i<bullet.mesh.Npoints;i++)
>> > mtx_mul(&bullet.mesh[i], &bullet.mesh[i], &mtx);
>> >
>> > if that doesn't do what you expect, where do you expect the problem
>> > to lie?
>>
>> Now write that out without the little functions and explain why the
>> result is any easier to understand and debug.
>>
>> And how do did anglebetween, rotationmatrix and mtx_mul pass their
>> tests? What would you test in the version without the little functions?
>>
>
> Point2D a = bullet.heading;
> Point2D b = spaceship.heading;
>
> len = sqrt(a.x*a.x + a.y*a.y);
> a.x /= len; a.y/= len;
> len = sqrt(b.x*b.x + b.y*b.y);
> b.x /= len; b.y /= len;
> costheta = a.x * b.x + a.y * b.y;
> side = a.x * b.y - a.x * b.y > 0 ? 1 : -1;
> sintheta = sqrt(1 - costheta * costheta);
> sintheta *= side;
> for(i=0;i<bullet.mesh.Npoints;i++)
> {
> double tx, ty;
> tx = bullet.mesh[i].y * costheta - bullet.mesh[i].y * sintheta;
> ty = bullet.mesh[i].x * sintheta + bullet.mesh[i].y * costheta;
> bullet.mesh[i].x = tx;
> bullet.mesh[i].y = ty;
> }
>
> Now we can see where the errors are likely to be
This is one of those cases where the same evidence induces entirely
different conclusions. I suppose we can just let every one look and
decide for themselves!
I would much prefer to test, maintain and debug the first.
<snip>
--
Ben.
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Program to count words, issues with an if condition within a for loop Alla _ <modelling.data@gmail.com> - 2015-10-10 10:28 -0700
Re: Program to count words, issues with an if condition within a for loop Stephen Fisher <sfisher@panix.com> - 2015-10-10 18:53 +0000
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-10 22:23 +0200
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-10 23:13 +0200
Re: Operating Systems in Teaching Bartc <bc@freeuk.com> - 2015-10-10 22:04 +0100
Re: Operating Systems in Teaching Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-10 14:12 -0700
Re: Operating Systems in Teaching Bartc <bc@freeuk.com> - 2015-10-10 22:30 +0100
Re: Operating Systems in Teaching Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-10-10 18:25 -0400
Re: Operating Systems in Teaching Bartc <bc@freeuk.com> - 2015-10-11 15:02 +0100
Re: Operating Systems in Teaching Bartc <bc@freeuk.com> - 2015-10-11 16:39 +0100
Re: Operating Systems in Teaching Melzzzzz <mel@zzzzz.com> - 2015-10-11 17:50 +0200
Re: Operating Systems in Teaching "Osmium" <r124c4u102@comcast.net> - 2015-10-11 11:29 -0500
Re: Operating Systems in Teaching "Osmium" <r124c4u102@comcast.net> - 2015-10-11 11:48 -0500
Re: Operating Systems in Teaching Bartc <bc@freeuk.com> - 2015-10-11 18:18 +0100
Re: Operating Systems in Teaching "Osmium" <r124c4u102@comcast.net> - 2015-10-11 12:46 -0500
Re: Operating Systems in Teaching Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2015-10-11 13:57 -0400
Re: Program to count words, issues with an if condition within a for loop Ian Collins <ian-news@hotmail.com> - 2015-10-11 10:21 +1300
Re: Program to count words, issues with an if condition within a for loop Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-10 14:55 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 00:35 +0200
Re: Program to count words, issues with an if condition within a for loop Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-11 00:01 +0100
Re: Program to count words, issues with an if condition within a for loop Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-10 16:21 -0700
Re: Program to count words, issues with an if condition within a for loop Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-11 01:24 +0100
Re: Program to count words, issues with an if condition within a for loop Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-10 17:56 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 03:17 +0200
Re: Program to count words, issues with an if condition within a for loop Ian Collins <ian-news@hotmail.com> - 2015-10-11 14:43 +1300
Re: Program to count words, issues with an if condition within a for loop Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-11 00:19 -0700
Re: Program to count words, issues with an if condition within a for loop Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-11 11:02 +0100
Re: Program to count words, issues with an if condition within a for loop Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-11 03:47 -0700
Re: Program to count words, issues with an if condition within a for loop Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-11 16:05 +0100
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 17:38 +0200
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 18:49 +0200
Re: Program to count words, issues with an if condition within a for loop Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-11 12:37 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 21:56 +0200
Re: Program to count words, issues with an if condition within a for loop Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-11 13:34 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-12 10:11 +0200
Re: Program to count words, issues with an if condition within a for loop Geoff <geoff@invalid.invalid> - 2015-10-11 12:59 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 19:15 +0200
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 12:48 +0200
Re: Program to count words, issues with an if condition within a for loop Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-11 03:59 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 13:30 +0200
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 14:19 +0200
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 14:48 +0200
Re: Program to count words, issues with an if condition within a for loop Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-11 12:20 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 13:49 +0200
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 13:55 +0200
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 02:40 +0200
Re: Program to count words, issues with an if condition within a for loop Ian Collins <ian-news@hotmail.com> - 2015-10-11 14:40 +1300
Re: Program to count words, issues with an if condition within a for loop Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-10 22:29 +0100
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 00:22 +0200
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 00:57 +0200
Re: Program to count words, issues with an if condition within a for loop Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-11 00:46 +0100
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 02:23 +0200
Re: Program to count words, issues with an if condition within a for loop Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-11 01:28 +0100
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 04:21 +0200
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 04:32 +0200
Re: Program to count words, issues with an if condition within a for loop Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-11 11:06 +0100
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-11 02:55 +0200
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-15 10:36 -0700
Re: Program to count words, issues with an if condition within a for loop Geoff <geoff@invalid.invalid> - 2015-10-15 14:37 -0700
Re: Program to count words, issues with an if condition within a for loop raltbos@xs4all.nl (Richard Bos) - 2015-10-11 10:15 +0000
Re: Program to count words, issues with an if condition within a for loop Rosario19 <Ros@invalid.invalid> - 2015-10-12 10:37 +0200
Re: Program to count words, issues with an if condition within a for loop Rosario19 <Ros@invalid.invalid> - 2015-10-12 11:08 +0200
Re: Program to count words, issues with an if condition within a for loop Rosario19 <Ros@invalid.invalid> - 2015-10-14 16:27 +0200
Re: Program to count words, issues with an if condition within a for loop Tonton Th <tTh@nowhere.invalid> - 2015-10-14 14:28 +0000
Re: Program to count words, issues with an if condition within a for loop Rosario19 <Ros@invalid.invalid> - 2015-10-14 16:36 +0200
Re: Program to count words, issues with an if condition within a for loop Rosario19 <Ros@invalid.invalid> - 2015-10-14 16:40 +0200
Re: Program to count words, issues with an if condition within a for loop Rosario19 <Ros@invalid.invalid> - 2015-10-14 16:49 +0200
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-15 14:09 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-16 12:49 +0200
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-19 14:28 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-20 02:03 +0200
Re: Program to count words, issues with an if condition within a for loop Ian Collins <ian-news@hotmail.com> - 2015-10-20 13:13 +1300
Re: Program to count words, issues with an if condition within a for loop Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-19 20:07 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-20 14:30 +0200
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-20 15:08 +0200
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-24 12:18 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-20 03:03 +0200
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-24 12:21 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-25 15:16 +0100
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-27 22:29 -0700
Re: Program to count words, issues with an if condition within a for loop raltbos@xs4all.nl (Richard Bos) - 2015-10-11 10:26 +0000
Re: Program to count words, issues with an if condition within a for loop Keith Thompson <kst-u@mib.org> - 2015-10-11 14:09 -0700
Re: Program to count words, issues with an if condition within a for loop raltbos@xs4all.nl (Richard Bos) - 2015-10-14 11:36 +0000
Re: Program to count words, issues with an if condition within a for loop Keith Thompson <kst-u@mib.org> - 2015-10-14 10:23 -0700
Re: Program to count words, issues with an if condition within a for loop raltbos@xs4all.nl (Richard Bos) - 2015-10-20 16:06 +0000
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-12 00:19 +0200
Re: Program to count words, issues with an if condition within a for loop Keith Thompson <kst-u@mib.org> - 2015-10-11 17:53 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-12 04:15 +0200
Re: Program to count words, issues with an if condition within a for loop Alla _ <modelling.data@gmail.com> - 2015-10-13 08:44 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-14 07:27 +0200
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-14 08:53 +0200
Re: Program to count words, issues with an if condition within a for loop Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-14 11:13 +0100
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-14 12:35 +0200
Re: Program to count words, issues with an if condition within a for loop Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-14 13:08 +0100
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-14 18:11 +0200
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-16 04:58 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-16 15:07 +0200
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-16 23:50 +0200
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-17 00:06 +0200
Re: Program to count words, issues with an if condition within a for loop Keith Thompson <kst-u@mib.org> - 2015-10-16 15:30 -0700
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-19 13:45 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-20 02:40 +0200
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-24 12:47 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-25 15:36 +0100
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-27 22:37 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-25 15:52 +0100
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-25 19:10 +0100
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-25 19:17 +0100
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-27 23:05 -0700
Re: Program to count words, issues with an if condition within a for loop Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-28 03:59 -0700
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-29 14:04 +0100
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-29 01:07 +0100
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-30 08:31 -0700
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-27 22:48 -0700
Re: Program to count words, issues with an if condition within a for loop Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-20 08:55 +0000
Re: Program to count words, issues with an if condition within a for loop regis <regis.barbanchon@free.fr> - 2015-10-20 13:52 +0200
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-24 14:04 -0700
Re: Program to count words, issues with an if condition within a for loop Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-25 06:44 +0000
Re: Program to count words, issues with an if condition within a for loop raltbos@xs4all.nl (Richard Bos) - 2015-10-25 09:09 +0000
Re: Program to count words, issues with an if condition within a for loop Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-10-25 10:12 +0000
Re: Program to count words, issues with an if condition within a for loop asetofsymbols@gmail.com - 2015-10-25 03:26 -0700
Re: Program to count words, issues with an if condition within a for loop Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-10-25 06:38 -0700
Re: Program to count words, issues with an if condition within a for loop Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-25 15:23 +0000
Re: Program to count words, issues with an if condition within a for loop supercat@casperkitty.com - 2015-10-25 10:54 -0700
Re: Program to count words, issues with an if condition within a for loop Keith Thompson <kst-u@mib.org> - 2015-10-25 12:21 -0700
Re: Program to count words, issues with an if condition within a for loop supercat@casperkitty.com - 2015-10-25 14:16 -0700
Re: Program to count words, issues with an if condition within a for loop Keith Thompson <kst-u@mib.org> - 2015-10-25 14:52 -0700
Re: Program to count words, issues with an if condition within a for loop Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-10-26 00:58 +0000
Re: Program to count words, issues with an if condition within a for loop Bartc <bc@freeuk.com> - 2015-10-26 11:50 +0000
Re: Program to count words, issues with an if condition within a for loop raltbos@xs4all.nl (Richard Bos) - 2015-11-10 15:17 +0000
Re: Program to count words, issues with an if condition within a for loop Les Cargill <lcargill99@comcast.com> - 2015-11-10 19:27 -0600
Re: Program to count words, issues with an if condition within a for loop Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-11-11 07:39 +0000
Re: Program to count words, issues with an if condition within a for loop Les Cargill <lcargill99@comcast.com> - 2015-11-11 08:22 -0600
Re: Program to count words, issues with an if condition within a for loop Robert Wessel <robertwessel2@yahoo.com> - 2015-11-11 00:37 -0600
Re: Program to count words, issues with an if condition within a for loop Tim Rentsch <txr@alumni.caltech.edu> - 2015-10-28 08:52 -0700
Re: Program to count words, issues with an if condition within a for loop Barry Schwarz <schwarzb@dqel.com> - 2015-10-18 12:31 -0700
Re: Program to count words, issues with an if condition within a for loop asetofsymbols@gmail.com - 2015-10-18 15:28 -0700
Re: Program to count words, issues with an if condition within a for loop Ian Collins <ian-news@hotmail.com> - 2015-10-19 11:40 +1300
Re: Program to count words, issues with an if condition within a for loop asetofsymbols@gmail.com - 2015-10-18 20:41 -0700
Re: Program to count words, issues with an if condition within a for loop asetofsymbols@gmail.com - 2015-10-18 20:44 -0700
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