C dynamic string array

The simplest way is:

char lines[100][1000];

Alternatively:

char* lines[100];
int i;
for (i = 0; i < 100; i++) {
  lines[i] = malloc(1000);
}
...
for (i = 0; i < 100; i++) {
  free(lines[i]);
}

The latter is a bit more flexible in that -- with minor modifications -- it permits you to allocate a different amount of memory for every string.

It looks like you want an array strings, each string holding at most 1000 characters.  There are some issues with your code.

1. You've declared an array of char *s but what you really want is a pointer to an array of chars.  For that, your declaration should be

   char (*lines)[1000];
   

2. On the other hand, you shouldn't forget about the NULL bytes at the end of strings, and should probably instead declare

   char (*lines)[1001];
   

3. To set the pointer, you'll want to use

   lines = (char (*)[1001]) malloc(100 * sizeof(char[1001]));
   

   or

   lines = (char (*)[1001]) malloc(100 * sizeof(*lines));
   

   the latter working because, with lines a pointer to an array of chars, *lines is a char[1001].  Remember to make sure you didn't get a NULL pointer back.

4. At the end, you should free the memory you've malloced with

   free(lines);
   

You can write a for-loop as:

char * lines[1000];

int i = 0;

for (i = 0; i < 1000; i++)
{
    lines[i] = (char*)malloc(100 * sizeof(lines));
}

Don't forget to free-up the memory pointed by all the pointers

for (i = 0; i < 1000; i++)
{
    free(lines[i])
}

Why don't you create a 2 dimensional array?