First we pull in the stocks.h header file from the libstocks library we are going to link in. Then we add the function prototypes for the two new functions we plan on adding. And finally, we create a simple little data structure for the stock pointer that the libstocks get_quotes() function returns. We need this because libstocks just uses a linked list of pointers. We need to keep track of both the top pointer so we can free the memory later and we also need the current pointer so we can walk through the linked list one by one. Here is our simple structure: