Dynamically allocate size of array for strings

Hello, guys! :-)

How to dynamically allocate size of *str?

This programm works fine, but in file can be more lines than i can provide, and i want to read their all! :-)

Or better write
#define MAXSTRINGS 5000
and don't **** my head? :-)

code:
-------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAXSTRLEN 4096
#define MAXSTRINGS 50

int main(void)
{
FILE *fp;
char *str[MAXSTRINGS]; /* ??? */
char buf[MAXSTRLEN];
int i;

fp = fopen(PATH, "r");
if (fp == NULL)
exit(1);

for(i=0; fgets(buf, MAXSTRLEN, fp) != NULL; i++) {
str[i] = strdup(buf);
if(str[i] == NULL)
exit(1);
}
str[i] = NULL;

fclose(fp);

for(i=0; str[i]; i++)
printf ("%s", str[i]);
return 0;
}
-------------------------------
THANKS!

Use a linked list then. Or use realloc and use a char ** for your array.

Quzah.

One option would be read the file twice. The first time count the number of lines in the file. Then use malloc() to allocate that many strings. Then read the file again.

OK, Thanks guys! :-)

Considering aforesaid i have written this code:

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAXSTRLEN        4096
#define SOMEFILE        "somefile.txt"

typedef struct list list;
struct list
{
        char *str;
        list *next;
};

list *item_new(char *str)
{
        list *lp;

        if (str == NULL)
                return NULL;
       
        lp = (list *) malloc(sizeof(list));
        if (lp == NULL)
                return NULL;
        lp->str  = str;
        lp->next = NULL;
       
        return lp;
}

list *item_add(list *lp, list *np)
{
        np->next = lp;
        return np;
}

void free_list(list *lp)
{
        list *next;

        for ( ; lp != NULL; lp = next) {
                next = lp->next;
                free(lp->str);
                free(lp);
        }
}

int main(void)
{
        FILE *fp;
        list *lp;
        char *tp, buf[MAXSTRLEN];

        lp = NULL;
        fp = fopen(SOMEFILE, "r");
        if (fp == NULL)
                exit(1);
        while (fgets(buf, MAXSTRLEN, fp) != NULL) {
                tp = strdup(buf);
                if (tp == NULL)
                        exit(1);
                lp = item_add(lp, item_new(tp));
        }               
        fclose(fp);

        for ( ; lp != NULL; lp = lp->next)
                printf ("%s", lp->str);

        free_list(lp);

        return 0;
}

---

Works fine, but i not certain that has done all correct, could not you correct me if i have allowed here blunders?
Thank you!

Seems pretty good

The only thing I can see is item_add doesn't guard against NULL pointers.

Two minor points
1. the (char*) cast on the malloc return is not necessary in ANSI-C. If you include stdlib.h there is no problem. However, if you fail to include stdlib.h, the cast suppresses an important warning.

2. strdup is not an ANSI-C function. If you've got it, use it - but bear in mind that some people will not have that function.

Thank you, Salem. :-)