switch on strings

**user923005** · Sep 25 '07, 06:25 AM

Re: switch on strings

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()
and
a conventional if/else chain. See also questions 10.12,
20.18,
and 20.29.

References: K&R1 Sec. 3.4 p. 55; K&R2 Sec. 3.4 p. 58; ISO
Sec. 6.6.4.2; H&S Sec. 8.7 p. 248.

**Martin Ambuhl** · Sep 25 '07, 06:55 AM

Re: switch on strings

sinbad wrote:

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

The control expression in a switch startement must be of an integral
type. Strings are not of integral type.

What you need to do is to map the string onto an integer and use that
integer as the control expression in the switch statement.

**karthikbalaguru** · Sep 25 '07, 10:05 AM

Re: switch on strings

On Sep 25, 11:49 am, Martin Ambuhl <mamb...@earthl ink.netwrote:

sinbad wrote:

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

>
The control expression in a switch startement must be of an integral
type. Strings are not of integral type.
>
What you need to do is to map the string onto an integer and use that
integer as the control expression in the switch statement.

Mapping will help u.

Karthik Balaguru

**michel.gareil@gmail.com** · Sep 25 '07, 03:05 PM

Re: switch on strings

Hi
may you can emulate a switch structure with a do while... something
like that :

do
{

/* first case : */
if( strcmp(someStri ng, refString ) == 0 )
{
/* any action */
break ;
}
/* second case : */
if( strcmp(anotherS tring, refString ) == 0 )
{
/* any action */
break ;
}

/* here can come the default : branch */

}while( 0 ) ;

Hope it will help :-)

Regards

On 25 sep, 12:04, karthikbalaguru <karthikbalagur ...@gmail.comwr ote:

On Sep 25, 11:49 am, Martin Ambuhl <mamb...@earthl ink.netwrote:
>

sinbad wrote:

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

>

The control expression in a switch startement must be of an integral
type. Strings are not of integral type.

>

What you need to do is to map the string onto an integer and use that
integer as the control expression in the switch statement.

>
Mapping will help u.
>
Karthik Balaguru

**Jack Klein** · Sep 25 '07, 04:35 PM

Re: switch on strings

On Tue, 25 Sep 2007 15:02:20 -0000, michel.gareil@g mail.com wrote in
comp.lang.c:

Hi

Hi yourself. Don't top-post here, when you write a reply your new
material belongs AFTER the quoted material in the original post you
are responding to.

may you can emulate a switch structure with a do while... something
like that :
>
do
{
>
/* first case : */
if( strcmp(someStri ng, refString ) == 0 )
{
/* any action */
break ;
}
/* second case : */
if( strcmp(anotherS tring, refString ) == 0 )
{
/* any action */
break ;
}
>
/* here can come the default : branch */
>
}while( 0 ) ;

And you can replace the clumsy structure above with:

if (strcmp(str1, test_str) == 0)
{
/* whatever */
}
else if (strcmp(str2,te st_str) == 0)
{
/* different whatever */
}
else
{
/* default for no match */
}

Then no dummy do ... while loop or break statements clutter up the
readability.

--
Jack Klein
Home: http://JK-Technology.Com
FAQs for
comp.lang.c http://c-faq.com/
comp.lang.c++ http://www.parashift.com/c++-faq-lite/
alt.comp.lang.l earn.c-c++

http://www.club.cc.cmu.edu/~ajo/docs/FAQ-acllc.html

**Keith Thompson** · Sep 25 '07, 07:45 PM

Re: switch on strings

karthikbalaguru <karthikbalagur u79@gmail.comwr ites:
[...]

Mapping will help u.

Who is "u"?

When you post here, please don't use silly abbreviations like "u" for
"you". This is not a chat room. We'll certainly make allowances for
spelling and grammar, especially if English isn't your first language,
but please take the time to spell out words (and use proper
punctuation). Thank you.

--
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"

**Kenny McCormack** · Sep 25 '07, 07:55 PM

Re: switch on strings

In article <lnejgmzg4x.fsf @nuthaus.mib.or g>,
karthikbalaguru <karthikbalagur u79@gmail.comwr ote:

>karthikbalagur u <karthikbalagur u79@gmail.comwr ites:
>[...]

>Mapping will help u.

>
>Who is "u"?

to which
Keith Thompson <kst-u@mib.orgmeant to write:

>Whn y pst hr, pls dn't s slly bbrvtns lk "" fr
>"y". Ths s nt cht rm. W'll crtnly mk llwncs fr
>spllng nd grmmr, spclly f Englsh sn't yr frst lngg,
>bt pls tk th tm t spll t wrds (nd s prpr
>pncttn). Thnk y.

HTH. HAND.

**Richard Tobin** · Sep 25 '07, 08:35 PM

Re: switch on strings

In article <lnejgmzg4x.fsf @nuthaus.mib.or g>,
Keith Thompson <kst-u@mib.orgwrote:

>Mapping will help u.

>Who is "u"?

Traditionally, unix systems recorded various information about each
process in the "u area". I imagine mapping could be very useful in
implementing this.

-- Richard
--
"Considerat ion shall be given to the need for as many as 32 characters
in some alphabets" - X3.4, 1963.

**karthikbalaguru** · Sep 26 '07, 06:35 AM

Re: switch on strings

On Sep 26, 1:13 am, rich...@cogsci. ed.ac.uk (Richard Tobin) wrote:

In article <lnejgmzg4x.... @nuthaus.mib.or g>,
Keith Thompson <ks...@mib.orgw rote:
>

Mapping will help u.

Who is "u"?

>
Traditionally, unix systems recorded various information about each
process in the "u area". I imagine mapping could be very useful in
implementing this.
>
-- Richard
--
"Considerat ion shall be given to the need for as many as 32 characters
in some alphabets" - X3.4, 1963.

It should be 'you' and not 'u'.

Karthik Balaguru

**CBFalconer** · Sep 26 '07, 12:55 PM

Re: switch on strings

karthikbalaguru wrote:

rich...@cogsci. ed.ac.uk (Richard Tobin) wrote:

>Keith Thompson <ks...@mib.orgw rote:
>>

>>>Mapping will help u.
>>>
>>Who is "u"?

>>
>Traditionall y, unix systems recorded various information about
>each process in the "u area". I imagine mapping could be very
>useful in implementing this.

>
It should be 'you' and not 'u'.

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 from http://www.teranews.com

**Richard** · Sep 26 '07, 01:15 PM

Re: switch on strings

CBFalconer <cbfalconer@yah oo.comwrites:

karthikbalaguru wrote:

>rich...@cogsci .ed.ac.uk (Richard Tobin) wrote:

>>Keith Thompson <ks...@mib.orgw rote:
>>>
>>>>Mapping will help u.
>>>>
>>>Who is "u"?
>>>
>>Traditionally , unix systems recorded various information about
>>each process in the "u area". I imagine mapping could be very
>>useful in implementing this.

>>
>It should be 'you' and not 'u'.

>
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>

If you posted correctly then you could talk about signature
snipping. What *is* wrong with you?

I can't be arsed to manually cut your *first* signature off when I have
an automatic method which works for everyone else who posts to usenet
standards with a single signature. The fact that teranews adds another
sig is neither here nor there. There are multiple other FREE news
servers you could use which do not add this PITA second signature.

Please do not net nanny until you see fit to apply the same rules to
yourself.

**Keith Thompson** · Sep 26 '07, 08:05 PM

Re: switch on strings

Richard <rgrdev@gmail.c omwrites:

CBFalconer <cbfalconer@yah oo.comwrites:

[...]

>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>

>
If you posted correctly then you could talk about signature
snipping. What *is* wrong with you?

[...]

Please don't quote signatures. If your newsreader doesn't properly
snip them for you, then *do it yourself*. Is manually deleting four
or so lines of text too difficult for you, when you generally should
be manually deleting large chunks of the quoted parent article anyway?
Sheesh.

Yes, Chuck's signature is longer than it should be. Yes, the fact
that his signature has an additional "-- " line within it causes minor
problems for some software, problems that can easily be worked around.
The point has been made.

--
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"

**Richard** · Sep 26 '07, 08:35 PM

Re: switch on strings

Keith Thompson <kst-u@mib.orgwrites :

Richard <rgrdev@gmail.c omwrites:

>CBFalconer <cbfalconer@yah oo.comwrites:

[...]

>>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>

>>
>If you posted correctly then you could talk about signature
>snipping. What *is* wrong with you?

[...]
>
Please don't quote signatures. If your newsreader doesn't properly
snip them for you, then *do it yourself*. Is manually deleting four
or so lines of text too difficult for you, when you generally should
be manually deleting large chunks of the quoted parent article anyway?
Sheesh.
>
Yes, Chuck's signature is longer than it should be. Yes, the fact

I don't care about that. The fact is he breaks the "commons sense" rules
with his double sig and it breaks Gnus, SLRN to name but two. his sig
could be 1000 lines long for all I care - so long as it is correctly
delimited. Yes, i read all that baloney about how the RFC says this and
that and how news readers "should" be able to cope with it. But to
repeat myself - it is him and him ONLY who breaks this common sense
rule of having ONE "-- " clause.

that his signature has an additional "-- " line within it causes minor
problems for some software, problems that can easily be worked around.

No, it can not be "easily" worked around. Only manually in my case, and
I am not rewriting the elisp in one of the most powerful, oldest
newsreaders in existance because Mr CBFalconer sees fit to flaunt the
standards. Maybe that makes me as bad as him. I don't know and I don't
care.

The point has been made.

Sorry. No. "Chuck" repeatedly refuses to live by the rules he set. or to
listen to anyone. There are oodles of free alternatives to teranews. The
fact that he even commented on the previous poster needing to learn how
to snip signatures is just too much.

Possibly because it his him that I am so annoyed. He is constantly
whining and lecturing people on petty posting issues and yet thinks he
himself is above his own rules.

Yes, I am being petty. I don't necessarily like killfiles as I find them
the resort of the weak and small minded.

**Old Wolf** · Sep 26 '07, 10:15 PM

Re: switch on strings

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..

switch on strings

switch on strings

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