Easiest way to realloc

Question

I was just curoius is what is the easiest way to realloc memory? On my faculty we've used this code to realloc memory (example):

if (dat = fopen(argv[1], "rb")) {
    do {
      p = fread(&art, sizeof(ARTIKAL), 1, dat);
      if (p) {
        if (n == c) niz = (ARTIKAL *)realloc(niz, (c *= 2) * sizeof(ARTIKAL));
        niz[n++] = art;
      }
    } while (p);
    fclose(dat);

I'm thinking about using rewind function but I'm not 100% sure how could I implement it.

Answer 1

Why would you need a rewind() function in this example?

Your example seems to be fine, one thing that can be improved:

if (dat = fopen(argv[1], "rb")) {
do {
  p = fread(&art, sizeof(ARTIKAL), 1, dat);
  if (p) {
    if (n == c) 
    {
       ARTIKAL *tmp = (ARTIKAL *)realloc(niz, (c *= 2) * sizeof(ARTIKAL));

       if (tmp == NULL)
       {
         printf("Not enough memory!\n")
         return 0;
       }
       else
       {
         niz = tmp;
       }

    niz[n++] = art;
  }
} while (p);
fclose(dat);

buy adding the above, your code is safer, since realloc returns NULL when it fails to allocate space, and you then loose your data.