Using arrow -> and dot . operators together in C

Question

I was under the impression that it was possible to access data from a sub-node of a linked list or similar structure by using the arrow and dot operators together like so:

Answer 1

Use -> for pointers; use . for objects.

In your specific case you want

if (sample->left->num > sample->right->num)

because all of sample, sample->left, and sample->right are pointers.

If you convert any of those pointers in the pointed to object; use . instead

struct a copyright;
copyright = *(sample->right);
// if (sample->left->num > copyright.num)
if (*(sample->left).num > copyright.num)