problem with return

Hi all,
>
I am trying to understand why this function fails to return a string.
Can anyone help?
>
*************
#include <stdio.h>
#include <stdarg.h>
>
char set(char *item, int num, ...);
>
int main(void) {
char *Item;
char Ret;
printf("%s\n", set(item,4, "apple", "pear", "banana", "grape"));
}
char set(char *Item, int num, ...) {
va_list ap;
int i;
char all[50];

va_start(ap, num);
for (i=0; i<num;i++) {
if (i==0)
strcpy(all,item=va_arg(ap,char *));
else
strcat(all,item=va_arg(ap,char *));

I am trying to understand why this function fails to return a string.

Can anyone help?

#include <stdio.h>
#include <stdarg.h>

char set(char *item, int num, ...);

int main(void) {
char *Item;
char Ret;
printf("%s\n", set(item,4, "apple", "pear", "banana", "grape"));
}
char set(char *Item, int num, ...) {
va_list ap;
int i;
char all[50];
va_start(ap, num);
for (i=0; i<num;i++) {
if (i==0)
strcpy(all,item=va_arg(ap,char *));
else
strcat(all,item=va_arg(ap,char *));
}
va_end(ap);
return all;
}

Hi all,
>
I am trying to understand why this function fails to return a string.
Can anyone help?
>
*************
#include <stdio.h>
#include <stdarg.h>
>
char set(char *item, int num, ...);

Hi all,
>
I am trying to understand why this function fails to return a string.
Can anyone help?
>
*************
#include <stdio.h>
#include <stdarg.h>
>
char set(char *item, int num, ...);
>
int main(void) {
char *Item;
char Ret;
printf("%s\n", set(item,4, "apple", "pear", "banana", "grape"));
}
char set(char *Item, int num, ...) {

va_list ap;
int i;
char all[50];
va_start(ap, num);
for (i=0; i<num;i++) {
if (i==0)
strcpy(all,item=va_arg(ap,char *));
else
strcat(all,item=va_arg(ap,char *));
}
va_end(ap);
return all;

}
****************
>
Thanks in advance.
>
Sheldon
>

Hi all,
>
I am trying to understand why this function fails to return a string.
Can anyone help?
>
*************
#include <stdio.h>
#include <stdarg.h>
>
char set(char *item, int num, ...);
>
int main(void) {
char *Item;
char Ret;
printf("%s\n", set(item,4, "apple", "pear", "banana", "grape"));
}

Sheldon <shejo284@gmail.comwrote:
>>
Who knows? You clearly didn't post your actual code; the code you
posted is broken.
>>
Compare your code:
>>>>
with this, which your code may or may not resemble:
>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <stdlib.h>
>
char *set(char **item, int num, ...);
>
int main(void) {
char *item;
printf("%s\n", set(&item,4, "apple", "pear", "banana", "grape"));
return 0;
}
>
char *set(char **item, int num, ...) {
va_list ap;
int i;
char *all=malloc(50); /* assume success */
*all=0;
va_start(ap, num);
for (i=0; i<num;i++) {
strcat(all,*item=va_arg(ap,char *));
}
va_end(ap);
return all;
}
>
--
C. Benson Manica | I *should* know what I'm talking about - if I
cbmanica(at)gmail.com | don't, I need to know. Flames welcome.

Sheldon wrote:>
Make that:
"static char all[50]"
Your function returns a pointer which is invalid
as soon as the function returns. Making it static
will resolve that. It is not the most elegant solution,
however, and you might consider passing in a buffer.
(Which is what the first argument feels like it should be,
by the way. It's very odd to pass in that argument and
then use it as a local variable (which is ignored!)
the way you're doing.)
>>
And realize that this will be a very likely cause
of future bugs as you overflow the buffer. Keep
track of the length and use strncat, or do something
else to avoid the overflow.
>
--
Bill Pursell

I am very new in the world of C, only a few weeks. I am trying to learn
fast and along the way mistakes occur. Your code is certainly better
than mine but I was after an explanation as to why.

Sheldon <shejo284@gmail.comwrote:
>>
I apologize for being more unfriendly than was necessary, but I
assumed that your real code compiled, which the code you posted did
not. Enough people fail to post their real code that I jumped to that
conclusion in your case. In any case there were other errors with
your code - among them being that you failed to include <string.h>, as
well as other errors pointed out by other posters.
>
--
C. Benson Manica | I *should* know what I'm talking about - if I
cbmanica(at)gmail.com | don't, I need to know. Flames welcome.