adding chars to a string

[Rick]

Hi,

This is probably simple byt when you never did pointers and being used to
luxery strings like in Delphi or Visual Basic, C can get though. What I'm
trying to do is to add chars to a string. I looked in the string.h file but
I didn't find that kind of function (that string library is more than 7
years old) so I decided to write that function on myself. It seems to work
although when I'm trying to do printf's between those actions I get strange
messages. Anyway, now I'm trying to add chars to 2 strings. The first string
is ok but the second one seems to get overwrited. Here's my code :

/* the function to add 1 char to a string */

char *strAddChar(cha r *s1, char c){
char *s;
s = s1;
s = s + strlen(s1); // the position to write
*s = c; // this should be on the place where the null char
first
// was.
s++;
*s = 0; // add a new null string
return(s1);
} // strAddChar

/* this is how I use the function */
main(){
char *res1 = ""; // empty string 1
char *res2 = ""; // empty string 2
strAddChar( res1, 'a' );
strAddChar( res1, 'b' );
strAddChar( res1, 'c' );
strAddChar( res2, '1' );
strAddChar( res2, '2' );
strAddChar( res2, '3' );
printf( "%s\n",res1 ); // test
printf( "%s\n",res2 );

Ok, the output should be res1="abc" and res2="123" but this is my result :
res1="abc" res2="bc123"
How does "bc" come in res2?? How to fix the function?

Greetings,
Rick

[Dan Pop]

In <bn**********@c hessie.cirr.com > Christopher Benson-Manica <at***@nospam.c yberspace.org> writes:

Kevin Goodsell <us************ *********@never box.com> spoke thus:

Unless you are using a C99 compiler (extremely unlikely), the above
"comment" is a syntax error. Use /* */ comments instead.

Well, it isn't conforming, but he could easily have a compiler that supports
this extension...

Which requires a diagnostic, once he's using his compiler as a conforming
C89 compiler, because, with one exception (//*) // is a syntax error in
C89.

Dan
--
Dan Pop
DESY Zeuthen, RZ group
Email: Da*****@ifh.de

[Dan Pop]

In <9u************ *************** *****@4ax.com> Irrwahn Grausewitz <ir*******@free net.de> writes:

David Rubin <fu******@warpm ail.net> wrote:

[...] Also, starting a function with 'str' violates the
implementatio n namespace.

But only if followed by a lowercase letter, thus the OP is safe
declaring a function named strAddChar.

External identifiers need not be case sensitive in C89!

Dan
--
Dan Pop
DESY Zeuthen, RZ group
Email: Da*****@ifh.de

[CBFalconer]

"L.J. Buitinck" wrote:

.... snip ...
if your system has them, consider using strlcpy()/strlcat().
http://www.openbsd.org/papers/strlcpy-paper.ps

if your system doesn't have them, you can get source for them at:

<http://cbfalconer.home .att.net/download/>

--
Chuck F (cb********@yah oo.com) (cb********@wor ldnet.att.net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home .att.net> USE worldnet address!

[Irrwahn Grausewitz]

Da*****@cern.ch (Dan Pop) wrote:

In <9u************ *************** *****@4ax.com> Irrwahn Grausewitz <ir*******@free net.de> writes:

David Rubin <fu******@warpm ail.net> wrote:

[...] Also, starting a function with 'str' violates the
implementati on namespace.

But only if followed by a lowercase letter, thus the OP is safe
declaring a function named strAddChar.

External identifiers need not be case sensitive in C89!

Umph, right, I was referring to C99 but didn't say so.
--
Irrwahn
(ir*******@free net.de)