switch on strings

**Keith Thompson** · Sep 26 '07, 10:55 PM

Re: switch on strings

Old Wolf <oldwolf@inspir e.net.nzwrites:

On Sep 27, 12:08 am, CBFalconer <cbfalco...@yah oo.comwrote:

>Well done. Now maybe the lesson will stick. Add to it the need
>for propper snipping, especially of sigs.
>>
>--
> Chuck F (cbfalconer at maineline dot net)
> Available for consulting/temporary embedded and systems.
> <http://cbfalconer.home .att.net>
>>
>--
>Posted via a free Usenet account fromhttp://www.teranews.co m

>
Physician, heal thyself..

Chuck doesn't have a problem with snipping of sigs, i.e., with
deleting signatures from quoted material. If he criticized others for
having signatures that are too long, or that have embedded "-- "
lines, your argument would be stronger.

--
Keith Thompson (The_Other_Keit h) kst-u@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <* <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

**iesvs@free.fr** · Sep 27 '07, 06:45 PM

Re: switch on strings

Maybe we should all club together and give Chuck an annual $29.95

standard Teranews account for Christmas... I'll pledge the first $1 :)

You pay to use the news ? Really ?

**Default User** · Sep 27 '07, 09:15 PM

Re: switch on strings

iesvs@free.fr wrote:

Maybe we should all club together and give Chuck an annual $29.95
standard Teranews account for Christmas... I'll pledge the first $1
:)

>
You pay to use the news ? Really ?

Yes. Google Groups is one of the worst ways to access newsgroups. It's
really, really, bad.

A real news service and dedicated newsreader are far superior.

Brian

**Mark McIntyre** · Sep 29 '07, 11:45 AM

Re: switch on strings

On Sat, 29 Sep 2007 11:19:53 +0530, in comp.lang.c , santosh
<santosh.k83@gm ail.comwrote:

>Err no. There are free news servers too. And not just aioe.org. He could use
>one of those.

TAANSTAFL.

I have a "free" news server as part of my ISP deal. Its about as much
use as a chocolate teapot.

But hey, picking on Chuck because of something beyond his reasonable
control is way more fun than answering actual questions about C. so
why not continue?
--
Mark McIntyre

"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it."
--Brian Kernighan

**santosh** · Sep 29 '07, 01:55 PM

Re: switch on strings

Mark McIntyre wrote:

On Sat, 29 Sep 2007 11:19:53 +0530, in comp.lang.c , santosh
<santosh.k83@gm ail.comwrote:
>

>>Err no. There are free news servers too. And not just aioe.org. He could
>>use one of those.

>
TAANSTAFL.
>
I have a "free" news server as part of my ISP deal. Its about as much
use as a chocolate teapot.

In my experience, I've found motrazella.org to be quite responsive. It needs
a registration, but is otherwise free. But, as another poster to this
thread noted, Chuck apparently posts hundreds of messages a day, so it may
be that free offerings are ill-suited for him.

But hey, picking on Chuck because of something beyond his reasonable
control is way more fun than answering actual questions about C. so
why not continue?

Well, for my part, I've not raised any issue WRT Chuck's sig[s]. The
previous post was a response to your statement up-thread.

**Spiros Bousbouras** · Sep 29 '07, 02:05 PM

Re: switch on strings

On 27 Sep, 13:11, CBFalconer <cbfalco...@yah oo.comwrote:

There is no prohibition against a sig
marker appearing within a sig.

So how is a newsreader supposed to know how much to snip then ?

**santosh** · Sep 29 '07, 02:35 PM

Re: switch on strings

Spiros Bousbouras wrote:

On 27 Sep, 13:11, CBFalconer <cbfalco...@yah oo.comwrote:

>There is no prohibition against a sig
>marker appearing within a sig.

>
So how is a newsreader supposed to know how much to snip then ?

Presumably snip all text after the first instance of sig delimiter?

**Mark McIntyre** · Sep 29 '07, 07:05 PM

Re: switch on strings

On Sat, 29 Sep 2007 07:00:38 -0700, in comp.lang.c , Spiros Bousbouras
<spibou@gmail.c omwrote:

>On 27 Sep, 13:11, CBFalconer <cbfalco...@yah oo.comwrote:

>There is no prohibition against a sig
>marker appearing within a sig.

>
>So how is a newsreader supposed to know how much to snip then ?

line = readline()
while (line != NULL)
if (left(line, 3) == "-- ") then goto nomorepost
putline(">" & line)
line = readline()
wend
nomorepost:

--
Mark McIntyre

"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it."
--Brian Kernighan

**Lew Pitcher** · Oct 1 '07, 02:35 PM

Re: switch on strings

On Sep 25, 2:20 am, user923005 <dcor...@connx. comwrote:

On Sep 24, 11:19 pm, sinbad <sinbad.sin...@ gmail.comwrote:
>

how to implement a switch case for stringse...swit ch should happen
depending on the strings...

>
Suggestion: do a web search for "perfect hash".
>

From the C FAQ:

>
20.17: Is there a way to switch on strings?
>
A: Not directly. Sometimes, it's appropriate to use a separate
function to map strings to integer codes, and then switch on
those. Otherwise, of course, you can fall back on strcmp()

[snip]

For example....

#include <stdarg.h>
#include <stdlib.h>

/*
** string compare string Match to list of strings starting with Model
** return ordinal of successful match (>=0) or -1 on no match
*/

int WhichString(cha r *Match, ...)
{
va_list arg;
int ordinal = 0;
char *item;

va_start(arg,Ma tch);
for(item=va_arg (arg, char *);item != NULL; item=va_arg(arg , char *))
{
if (strcmp(Match,i tem) == 0)
break;
else
++ordinal;
}
va_end(arg);

return (item != NULL ? ordinal : -1 );
}

And used like...

#include <stdio.h>

int WhichString(cha r *model, ...);

int main(int argc, char **argv)
{
enum {left,right,for ward,back,up,do wn,halt} cmd;

while (--argc)
switch (cmd = WhichString(*++ argv,
"left",
"right",
"forward",
"back",
"up",
"down",
"halt",
NULL))
{
case left: /* "left" */
puts("<--");
break;
case right: /* "right" */
puts("-->");
break;
case forward: /* "forward" */
puts(" <>");
break;
case back: /* "back" */
puts(" ><");
break;
case up: /* "up" */
puts(" ^\n |");
break;
case down: /* "down" */
puts(" |\n v");
break;
case halt: /* "halt" */
puts(" @\n !");
break;
case -1:
default:
puts("*** Unknown ***");
}

return 0;
}

**Francine.Neary@googlemail.com** · Oct 1 '07, 04:35 PM

Re: switch on strings

On Oct 1, 3:25 pm, Lew Pitcher <lpitc...@teksa vvy.comwrote:

On Sep 25, 2:20 am, user923005 <dcor...@connx. comwrote:On Sep 24, 11:19 pm, sinbad <sinbad.sin...@ gmail.comwrote:
>

how to implement a switch case for stringse...swit ch should happen
depending on the strings...

>

Suggestion: do a web search for "perfect hash".

>

>From the C FAQ:

>

20.17: Is there a way to switch on strings?

>

A: Not directly. Sometimes, it's appropriate to use a separate
function to map strings to integer codes, and then switch on
those. Otherwise, of course, you can fall back on strcmp()

>
[snip]
>
For example....
>
#include <stdarg.h>
#include <stdlib.h>
>
/*
** string compare string Match to list of strings starting with Model
** return ordinal of successful match (>=0) or -1 on no match
*/
>
int WhichString(cha r *Match, ...)
{
va_list arg;
int ordinal = 0;
char *item;
>
va_start(arg,Ma tch);
for(item=va_arg (arg, char *);item != NULL; item=va_arg(arg , char *))
{
if (strcmp(Match,i tem) == 0)
break;
else
++ordinal;
}
va_end(arg);
>
return (item != NULL ? ordinal : -1 );
>
}
>
And used like...
>
#include <stdio.h>
>
int WhichString(cha r *model, ...);
>
int main(int argc, char **argv)
{
enum {left,right,for ward,back,up,do wn,halt} cmd;
>
while (--argc)
switch (cmd = WhichString(*++ argv,
"left",
"right",
"forward",
"back",
"up",
"down",
"halt",
NULL))
{
case left: /* "left" */
puts("<--");
break;
case right: /* "right" */
puts("-->");
break;
case forward: /* "forward" */
puts(" <>");
break;
case back: /* "back" */
puts(" ><");
break;
case up: /* "up" */
puts(" ^\n |");
break;
case down: /* "down" */
puts(" |\n v");
break;
case halt: /* "halt" */
puts(" @\n !");
break;
case -1:
default:
puts("*** Unknown ***");
}
>
return 0;
>
}

Ouch! All those strcmps! Why not a simple hash function?

**Lew Pitcher** · Oct 1 '07, 06:25 PM

Re: switch on strings

On Oct 1, 12:25 pm, Francine.Ne...@ googlemail.com wrote:

On Oct 1, 3:25 pm, Lew Pitcher <lpitc...@teksa vvy.comwrote:
>
>
>

On Sep 25, 2:20 am, user923005 <dcor...@connx. comwrote:On Sep 24, 11:19 pm, sinbad <sinbad.sin...@ gmail.comwrote:

>

how to implement a switch case for stringse...swit ch should happen
depending on the strings...

>

Suggestion: do a web search for "perfect hash".

>

From the C FAQ:

>

20.17: Is there a way to switch on strings?

>

A: Not directly. Sometimes, it's appropriate to use a separate
function to map strings to integer codes, and then switch on
those. Otherwise, of course, you can fall back on strcmp()

>

[snip]

>

For example....

>

#include <stdarg.h>
#include <stdlib.h>

>

/*
** string compare string Match to list of strings starting with Model
** return ordinal of successful match (>=0) or -1 on no match
*/

>

int WhichString(cha r *Match, ...)
{
va_list arg;
int ordinal = 0;
char *item;

>

va_start(arg,Ma tch);
for(item=va_arg (arg, char *);item != NULL; item=va_arg(arg , char *))
{
if (strcmp(Match,i tem) == 0)
break;
else
++ordinal;
}
va_end(arg);

>

return (item != NULL ? ordinal : -1 );

>

}

>

[snip]

Ouch! All those strcmps! Why not a simple hash function?

Sure, why not? Care to show an example of how a simple hash function
would be better?

**user923005** · Oct 1 '07, 07:55 PM

Re: switch on strings

On Oct 1, 11:17 am, Lew Pitcher <lpitc...@teksa vvy.comwrote:

On Oct 1, 12:25 pm, Francine.Ne...@ googlemail.com wrote:
>
>
>
>
>

On Oct 1, 3:25 pm, Lew Pitcher <lpitc...@teksa vvy.comwrote:

>

On Sep 25, 2:20 am, user923005 <dcor...@connx. comwrote:On Sep 24, 11:19 pm, sinbad <sinbad.sin...@ gmail.comwrote:

>

how to implement a switch case for stringse...swit ch should happen
depending on the strings...

>

Suggestion: do a web search for "perfect hash".

>

>From the C FAQ:

>

20.17: Is there a way to switch on strings?

>

A: Not directly. Sometimes, it's appropriate to use a separate
function to map strings to integer codes, and then switch on
those. Otherwise, of course, you can fall back on strcmp()

>

[snip]

>

For example....

>

#include <stdarg.h>
#include <stdlib.h>

>

/*
** string compare string Match to list of strings starting with Model
** return ordinal of successful match (>=0) or -1 on no match
*/

>

int WhichString(cha r *Match, ...)
{
va_list arg;
int ordinal = 0;
char *item;

>

va_start(arg,Ma tch);
for(item=va_arg (arg, char *);item != NULL; item=va_arg(arg , char *))
{
if (strcmp(Match,i tem) == 0)
break;
else
++ordinal;
}
va_end(arg);

>

return (item != NULL ? ordinal : -1 );

>

}

>
[snip]

Ouch! All those strcmps! Why not a simple hash function?

>
Sure, why not? Care to show an example of how a simple hash function
would be better?

In this particular case, a hash function is not needed. Just switch
on the first letter.

**Flash Gordon** · Oct 2 '07, 12:05 AM

Re: switch on strings

user923005 wrote, On 01/10/07 20:45:

On Oct 1, 11:17 am, Lew Pitcher <lpitc...@teksa vvy.comwrote:

>On Oct 1, 12:25 pm, Francine.Ne...@ googlemail.com wrote:

<snip>

>>Ouch! All those strcmps! Why not a simple hash function?

>Sure, why not? Care to show an example of how a simple hash function
>would be better?

>
In this particular case, a hash function is not needed. Just switch
on the first letter.

A very simple hash function which just takes the first letter as the has
value ;-)

Of course, that could give lots of collisions if the strings are changed
or added to.
--
Flash Gordon

switch on strings

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment