You never initialized head, so it points to some random location. You should do something along the lines of head = (doubly_linked_list*)malloc(sizeof(doubly_linked_list)) first. This will allocate a new doubly_linked_list struct and assign it to head. And of course you probably need to free it later
You never initialized
head, so it points to some random location. You should do something along the lines ofhead = (doubly_linked_list*)malloc(sizeof(doubly_linked_list))first. This will allocate a newdoubly_linked_liststruct and assign it tohead. And of course you probably need tofreeit later