双向循环链表实现文件C语言

/* DoubleCircularLinkedList.c -- 双向循环链表实现文件 */ #include "DoubleCircularDoubleCircularLinkedList.h" /* 局部函数声明 */ static Node * makeNode (const Item * const pi) ; /* 接口函数定义 */ BOOL Create_B (DoubleCircularLinkedList * const pl) { *pl = (struct doublecircularlinkedlist *) malloc (sizeof (struct doublecircularlinkedlist)) ; if (NULL == *pl) return FALSE ; (*pl) -> list = NULL ; (*pl) -> current = 0 ; return TRUE ; } BOOL IsEmpty_B (const DoubleCircularLinkedList * const pl) { if (0 == (*pl) -> current) return TRUE ; else return FALSE ; } BOOL Insert_B (const DoubleCircularLinkedList * const pl, const Item * const pi) { Node * new_node ; new_node = makeNode (pi) ; if (NULL == new_node) return FALSE ; if (IsEmpty_B (pl)) { new_node -> left = new_node -> right = new_node ; (*pl) -> list = new_node ; } else { (*pl) -> list -> right -> left = new_node ; new_node -> left = (*pl) -> list ; new_node -> right = (*pl) -> list -> right ; (*pl) -> list -> right = new_node ; } (*pl) -> current++ ; return TRUE ; } Node * Find_B (const DoubleCircularLinkedList * const pl, const Item * const pi) { Node * scan ; int i, num ; if (IsEmpty_B (pl)) return NULL ; for (i = 0, num = (*pl) -> current, scan = (*pl) -> list; i < num; i++) { if (scan -> item != *pi) scan = scan -> right ; else return scan ; } return NULL ; } BOOL Delete_B (const DoubleCircularLinkedList * const pl, const Item * const pi) { Node * target ; target = Find_B (pl, pi) ; if (NULL == target) return FALSE ; if (1 == (*pl) -> current) { target = (*pl) -> list ; (*pl) -> list = NULL ; } else { target -> left -> right = target -> right ; target -> right -> left = target -> left ; if (target == (*pl) -> list) (*pl) -> list = target -> right ; } free (target) ; (*pl) -> current-- ; return TRUE ; } void Traversal_B (const DoubleCircularLinkedList * const pl, void (* pfun) (const Node * const pn)) { Node * scan ; int i, num ; for (i = 0, num = (*pl) -> current, scan = (*pl) -> list; i < num; i++) { (* pfun) (scan) ; scan = scan -> right ; } putchar ('/n') ; } void Release_B (const DoubleCircularLinkedList * const pl) { Node * scan ; int i, num ; for (i = 1, num = (*pl) -> current, scan = (*pl) -> list; i < num; i++) { scan = scan -> right ; free (scan -> left) ; } free (*pl) ; } /* 局部函数定义 */ static Node * makeNode (const Item * const pi) { Node * new_node ; new_node = (Node *) malloc (sizeof (Node)) ; if (NULL == new_node) return NULL ; new_node -> item = *pi ; return new_node ; }