c - When to use arrow and when dot?

Question

I've read about it and I mostly get it, but this situation confused me a bit. Why don't we use arrow operator -> in scanf? I understand that dot is used for objects and arrow for pointers but here, g is a pointer to structure.

DOCUMENT *take(int *pn){
        DOCUMENT *g;
        printf("How much documents? ");
        scanf("%d", pn);
        g = (DOCUMENT *)calloc(*pn, sizeof(DOCUMENT));
        for (int i = 0; i < *pn; i++)
        {
            printf("Type in author, name of document and number of pages: ");
            scanf("%s %s %d", g[i].author, g[i].name, &g[i].s );
        }
        return g;
    }

question from:https://stackoverflow.com/questions/65901748/when-to-use-arrow-and-when-dot

Answer 1

The array index operator [] has a dereference built into it.

g[i] is exactly the same as *(g + i). So g[i] refers to a DOCUMENT, not a DOCUMENT * and thus you use the member access operator . instead of the pointer-to-member operator ->.