Joseph Martin wrote:
> I am a subscribee to the linux-c-programming listserv. I have
> tried to send the message there several times during the last few days
> with no luck. It's not getting bounced, but I'm not recieving it back in
> my mailbox either. Could you please post it for me? (Any maybe answer too?
> :)
Done.
> I am struggling with my long time nemesis again - strings in C. I
> have a function I'm writing that will read in a file, assign each line to
> a subscript in an array, and return the array. Problem is I can't get pass
> the returning. Suggestions welcome. Code follows. Thanks a ton.
>
> #include <stdio.h>
> #include <stdlib.h>
> #include "file.h"
>
> char *read_file()
> {
> char line[10][80];
> int i;
> FILE *budget;
>
> if((budget = fopen("/home/martinja/.bashrc", "r"))==NULL) {
> printf("Cannot open config file\n");
> exit(1);
> }
> for(i=0; i<10; i++) {
> fgets(line[i], 80, budget);
> printf("%s", line[i]); // This tests if line reads
> // correctly
> }
> fclose(budget);
> return ??? //help here please!
> }
You will need to dynamically allocate the memory to store the data.
The variable `line' will vanish once you return from the function.
Also, you probably want to return a `char **' rather than `char *'.
The attached program reads each line into a temporary buffer, and then
copies the string to dynamically allocated memory using strdup().
The array of pointers to each line is also dynamically allocated; the
array is resized as necessary using realloc().
--
Glynn Clements <[EMAIL PROTECTED]>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
char **read_file(const char *filename)
{
char buff[1024];
char **index;
int size, count;
FILE *fp;
fp = fopen(filename, "r");
if (!fp)
{
fprintf(stderr, "Cannot open config file\n");
exit(1);
}
size = 16;
index = malloc(size * sizeof(char *));
for (count = 0; ; count++)
{
if (!fgets(buff, sizeof(buff), fp))
break;
if (count >= size - 1)
{
size *= 2;
index = realloc(index, size * sizeof(char *));
}
index[count] = strdup(buff);
}
index[count] = NULL;
fclose(fp);
return index;
}
int main(void)
{
char **index;
int i;
index = read_file("/etc/passwd");
for (i = 0; index[i]; i++)
fputs(index[i], stdout);
return 0;
}
