代头节点的单脸表模型

typedef struct node *link;struct noed{int item;link next;};static link head = NULL;link make_node(int item){link p = malloc(sizeof *p);p->item = item;p->next = next;return p;}void indert(link p){p->next = head;head = p;}link delete(link p){link prev;if(p == head){head = p->next;return p;}for (prev = head; prev; prev = prev->next)if(prev->next == p){prev->next = p->next;return p;}return NULL;}/*第二种单链表删除操作，更为简洁*/link delete(link p){link *pnext;for (pnext = &head; *pnext; pnext = &(*penxt)->next)if(*pnext == p){*pnext = p->next;return p;}return NULL;}void print(link p){for (p = head; p; p = p->next)printf("%d/n", p->item);}void free_node(link p){free(p);}void destory(void){link q, p = head;head = NULL;while (p){q = p;p = p->next;free(q);}}void push(link p){insert(p);}link pop(void){if (head == NULL)return NULL;elsereturn delete(head);}