equivalent of chomp in perl

[lnatz]

Hi,
Is there an equivalent to the perl command chomp in C? And if there is
no exact equivalent command, how would I go about removing the "\n" at
the end of a stdin?

Thank you,
Natalie

[Keith Thompson]

"lnatz" <nm**********@g mail.comwrites:

Is there an equivalent to the perl command chomp in C?

No. (chomp removes a '\n' character from the end of a string.)

And if there is no exact equivalent command, how would I go about
removing the "\n" at the end of a stdin?

I presume that by "a stdin", you mean "a string obtained from stdin".

Search for the '\n' character and replace it with '\0'. Be prepared
to decide what to do if the string doesn't contain a '\n' character,
or if it contains one but not at the end.

Note that C strings are not like Perl strings. They don't
automatically re-size themselves. A C string isn't a data type; it's
a data *format*, a sequence of character terminated by '\0'. A string
is typically held in an array of char; changing a trailing '\n' to
'\0' will change the length of the string but not the size of the
array.

--
Keith Thompson (The_Other_Keit h) ks***@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.

[CBFalconer]

lnatz wrote:

>
Is there an equivalent to the perl command chomp in C? And if
there is no exact equivalent command, how would I go about
removing the "\n" at the end of a stdin?

int flushln(FILE *f) {
int ch;

while (('\n' != (ch = getc(f))) && (EOF != ch)) continue;
return ch;
}

--
Chuck F (cbfalconer at maineline dot net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home .att.net>

[Keith Thompson]

CBFalconer <cb********@yah oo.comwrites:

lnatz wrote:

>Is there an equivalent to the perl command chomp in C? And if
there is no exact equivalent command, how would I go about
removing the "\n" at the end of a stdin?

int flushln(FILE *f) {
int ch;

while (('\n' != (ch = getc(f))) && (EOF != ch)) continue;
return ch;
}

That's a useful function, but it's doesn't bear any particular
resemblance to Perl's chomp function.

--
Keith Thompson (The_Other_Keit h) ks***@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.

[james of tucson]

lnatz wrote:

Is there an equivalent to the perl command chomp in C?

Perl's chomp() is actually a fairly complex function, especially in a
list context.

Do you just want to remove a newline from a string?

void chomp(const char *s)
{
char *p;
while (NULL != s && NULL != (p = strrchr(s, '\n'))){
*p = '\0';
}
} /* chomp */

[Michal Nazarewicz]

james of tucson <jmcgill@[go_ahead_and_sp am_me].arizona.eduwri tes:

lnatz wrote:

>Is there an equivalent to the perl command chomp in C?

Perl's chomp() is actually a fairly complex function, especially in a
list context.

Do you just want to remove a newline from a string?

void chomp(const char *s)
{
char *p;
while (NULL != s && NULL != (p = strrchr(s, '\n'))){
*p = '\0';
}
} /* chomp */

What if '\n' is in the middle of string? (Moreover, it's not nice
telling you won't modify the argument and then modifying it.)

#v+
#include <string.h>

int chomp(char *str) {
if (!str || !*str) return 0;
while (str[1]) ++str;
if (*str!='\n') return 0;
*str = 0;
return '\n';
}
#v-

--
Best regards, _ _
.o. | Liege of Serenly Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michal "mina86" Nazarewicz (o o)
ooo +--<mina86*tlen.pl >---<jid:mina86*chr ome.pl>--ooO--(_)--Ooo--

[james of tucson]

Michal Nazarewicz wrote:

What if '\n' is in the middle of string?

Then don't touch it!

Moreover, it's not nice
telling you won't modify the argument and then modifying it.)

const char * means that the pointer is fixed, not that it points to some
immutable type.

[Jordan Abel]

2006-11-03 <_h************ ********@newsfe 10.phx>,
james of tucson wrote:

Michal Nazarewicz wrote:

>What if '\n' is in the middle of string?

Then don't touch it!

>Moreover, it's not nice
telling you won't modify the argument and then modifying it.)

const char * means that the pointer is fixed, not that it points to some
immutable type.

No, that would be char * const. which hardly matters anyway in function
arguments.

[james of tucson]

Jordan Abel wrote:

2006-11-03 <_h************ ********@newsfe 10.phx>,
james of tucson wrote:

>Michal Nazarewicz wrote:

>>What if '\n' is in the middle of string?

Then don't touch it!

>>Moreover, it's not nice
telling you won't modify the argument and then modifying it.)

const char * means that the pointer is fixed, not that it points to some
immutable type.

No, that would be char * const. which hardly matters anyway in function
arguments.

Seriously, am I wrong about this? I know that "const char[]" states
that the array contents will not be altered (K&R2, p40), but that's not
the situation here. Here we are talking about declaring a pointer to a
char as const, not that it is a pointer to a const array of chars.

[Jordan Abel]

2006-11-03 <Gy************ ****@newsfe15.p hx>,
james of tucson wrote:

Jordan Abel wrote:

>2006-11-03 <_h************ ********@newsfe 10.phx>,
james of tucson wrote:

>>Michal Nazarewicz wrote:

What if '\n' is in the middle of string?
Then don't touch it!

Moreover, it's not nice
telling you won't modify the argument and then modifying it.)
const char * means that the pointer is fixed, not that it points to some
immutable type.

No, that would be char * const. which hardly matters anyway in function
arguments.

Seriously, am I wrong about this? I know that "const char[]" states
that the array contents will not be altered (K&R2, p40), but that's not
the situation here. Here we are talking about declaring a pointer to a
char as const, not that it is a pointer to a const array of chars.

If you want the _pointer_ rather than what is pointed _at_ to be
constant, "const" goes after the * token.

char * const p;