/*Header file for Doubly Linked List*/ typedef struct dll_node_{ void *data; struct dll_node_ *left; struct dll_node_ *right; } dll_node_t; typedef struct dll_{ dll_node_t *head; } dll_t; /* Public Function declaration to create and return * a new empty doubly linked list*/ dll_t * get_new_dll(); /* Public Function declaration to add the appication * data to DLL*/ int add_data_to_dll(dll_t *dll, void *appn_data);