content

what is difference between notation 1) ```&(*arr[i])``` and 2) ```arr[i]``` ?
Why does 1) work and 2) fail w/ Segmentation fault?
works:
```
...
int load_arr(char *filename, struct arr_t **arr)
{
    ...    
    *arr = malloc(arr_size * sizeof(struct arr_t));

    for (int i = 0; i < arr_size; i++) {
        fscanf(fp,"%d %f %f", &(object.id), &(object.x), &(object.y));
        init_arr(&(*arr)[i], 1); 
        append_arr(&(*arr)[i], object);
    }
    ...    
}
```
doesn't work (but compiles fine):
```
...
int load_arr(char *filename, struct arr_t **arr)
{
    ...    
    *arr = malloc(arr_size * sizeof(struct arr_t));

    for (int i = 0; i < arr_size; i++) {
        fscanf(fp,"%d %f %f", &(object.id), &(object.x), &(object.y));
        init_arr(arr[i], 1); 
        append_arr(arr[i], object);
    }
    ...    
}
```
in version that doesn't work, it would run for first 2-3 iterations and then fail with segmentation fault 11. Valgrind would be suggesting error in init_arr or append_arr methods.
```
void init_arr(struct arr_t *c, int cap)
{
    assert(c != NULL);
    assert(cap >= 0);

    c->size = 0;
    c->capacity = cap;
    c->obj = malloc(cap * sizeof(struct obj_t));
    if(c->obj == NULL) {
        c->capacity = 0;
    }
}

void append_arr(struct arr_t *c, struct obj_t obj)
{
    if(c->size >= c->capacity) {
        int ns = c->capacity + ARR_CHUNK;
        resize_arr(c, ns);
    }
 
    c->obj[c->size++] = obj;
}
```