I am new to C and am using visual studio.
While writing this function I got this error(Pointer to incomplete class type is not allowed). I don't know why.

```
int Length(struct node* head) 
{
  struct node* current = head;
  int count = 0;
  while (current != NULL) 
   {
     count++;
     current = current->next;  <-- error here when pointing current to next
   }
  return count;
}

```