#ifndef DOUBLY_LINKED_LIST
#define DOUBLY_LINKED_LIST
#include
#include
#include

/*链表节点*/
typedef struct DoublyLinkedListNodeS{
    struct DoublyLinkedListNodeS *prev,*next;
}DoublyLinkedListNode;

typedef struct DoublyLinkedList{
    DoublyLinkedListNode root;//sentinel list element, only &root, root.prev, and root.next are used
    int length;
}DoublyLinkedList;

//初始化双向链表
DoublyLinkedList* DoublyLinkedList_Init();

//销毁链表
void DoublyLinkedList_Destory(DoublyLinkedList* list);

//链表长度
int DoublyLinkedList_Len(DoublyLinkedList* list);

//求头节点
DoublyLinkedListNode* DoublyLinkedList_Front(DoublyLinkedList* list);

//求尾节点
DoublyLinkedListNode* DoublyLinkedList_Back(DoublyLinkedList* list);

//在at位置后面插入e
DoublyLinkedListNode* DoublyLinkedList_InsertAfter(DoublyLinkedList* list, DoublyLinkedListNode* at,DoublyLinkedListNode* e);

//在at前面插入e，成功返回e
DoublyLinkedListNode* DoublyLinkedList_InsertBefore(DoublyLinkedList* list, DoublyLinkedListNode* at, DoublyLinkedListNode* e);

//在头部插入e
DoublyLinkedListNode* DoublyLinkedList_PushFront(DoublyLinkedList* list, DoublyLinkedListNode* e);

//在尾部插入e
DoublyLinkedListNode* DoublyLinkedList_PushBack(DoublyLinkedList* list, DoublyLinkedListNode* e);

//删除节点e,并返回被删除的e
DoublyLinkedListNode* DoublyLinkedList_Remove(DoublyLinkedList* list, DoublyLinkedListNode* e);

//将e移动到头部
void DoublyLinkedList_MoveFront(DoublyLinkedList* list, DoublyLinkedListNode* e);

//将e移动到尾部
void DoublyLinkedList_MoveBack(DoublyLinkedList* list, DoublyLinkedListNode* e);

#endif // DOUBLY_LINKED_LIST

#include "doublyLinkedList.h"

DoublyLinkedList* DoublyLinkedList_Init() {
    DoublyLinkedList *list = (DoublyLinkedList *)malloc(sizeof(DoublyLinkedList));
    if (list == NULL) {
        fprintf(stderr,"malloc DoublyLinkedList error.\n");
        return NULL;
    }
    list->length = 0;
    list->root.next = &list->root;
    list->root.prev = &list->root;
    return list;
}

//销毁链表
void DoublyLinkedList_Destory(DoublyLinkedList* list) {
    if (list != NULL) {
        free(list);
        list = NULL;
    }
}

int DoublyLinkedList_Len(DoublyLinkedList* list) {
    if (list == NULL) {
        return 0;
    }
    return list->length;
}

//求头节点
DoublyLinkedListNode* DoublyLinkedList_Front(DoublyLinkedList* list) {
    if (list == NULL || list->length == 0) {
        return 0;
    }
    return list->root.next;
}

//求尾节点
DoublyLinkedListNode* DoublyLinkedList_Back(DoublyLinkedList* list) {
    if (list == NULL || list->length == 0) {
        return 0;
    }
    return list->root.prev;
}

//在at后面插入e，成功返回e
DoublyLinkedListNode* DoublyLinkedList_InsertAfter(DoublyLinkedList* list, DoublyLinkedListNode* at, DoublyLinkedListNode* e) {
    if (list == NULL || at == NULL) {
        fprintf(stderr,"wrong argument\n");
        return NULL;
    }
    DoublyLinkedListNode* next = at->next;
    at->next = e;
    e->prev = at;
    e->next = next;
    next->prev = e;
    list->length++;
    return e;
}

//在at前面插入e，成功返回e
DoublyLinkedListNode* DoublyLinkedList_InsertBefore(DoublyLinkedList* list, DoublyLinkedListNode* at, DoublyLinkedListNode* e) {
    if (list == NULL || at == NULL) {
        fprintf(stderr, "wrong argument\n");
        return NULL;
    }
    return DoublyLinkedList_InsertAfter(list, at->prev, e);
}

//在头部插入e，返回e
DoublyLinkedListNode* DoublyLinkedList_PushFront(DoublyLinkedList* list, DoublyLinkedListNode* e) {
    return DoublyLinkedList_InsertAfter(list,&list->root,e);
}

//在尾部插入e,返回e
DoublyLinkedListNode* DoublyLinkedList_PushBack(DoublyLinkedList* list, DoublyLinkedListNode* e) {
    return DoublyLinkedList_InsertBefore(list, &list->root, e);
}

//删除节点e,并返回被删除的e
DoublyLinkedListNode* DoublyLinkedList_Remove(DoublyLinkedList* list, DoublyLinkedListNode* e) {
    if (list == NULL || e == NULL) {
        return NULL;
    }

    e->prev->next = e->next;
    e->next->prev = e->prev;
    e->next = NULL;
    e->prev = NULL;
    list->length--;
    return e;
}

//将e移动到头部
void DoublyLinkedList_MoveFront(DoublyLinkedList* list, DoublyLinkedListNode* e) {
    if(list == NULL || e == NULL){
        return;
    }

    DoublyLinkedList_InsertAfter(list, &list->root, DoublyLinkedList_Remove(list,e));
}

//将e移动到尾部
void DoublyLinkedList_MoveBack(DoublyLinkedList* list, DoublyLinkedListNode* e) {
    if (list == NULL || e == NULL) {
        return;
    }

    DoublyLinkedList_InsertBefore(list, &list->root, DoublyLinkedList_Remove(list, e));
}

新闻名称：C语言实现双向链表（DoublyLinkedList）
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