// 双向循环链表实现.cpp : 定义控制台应用程序的入口点。 #include<iostream>#include<stdio.h>#include<math.h>#define LEN sizeof(struct DSCriculist)using namespace std;typedef struct DSCriculist //定义结构体{	int data; //数据域	struct DSCriculist *prior;//前向指针域	struct DSCriculist *next; //后向指针域}DSCriculist;//函数声明部分void Error(char* s);//错误处理函数DSCriculist *Creat_DSCriculist(); //创建双向循环链表DSCriculist *Find_DSCriculist(DSCriculist & L, int i);//查找双向循环链表中第i个结点void Insert_DSCriculist(DSCriculist & L, int i, int e);//向双向循环链表中位置i处插入数据域为e的结点void Delete_DSCriculist(DSCriculist & L, int i, int e);//删除双向循环链表中第i个结点，并用e返回该结点数据域的值void Search_DSCriculist(DSCriculist &L, int e);//查找双向循环链表中数据域为e的结点，并输出int Getlength_DSCriculist(DSCriculist & L);//计算上相循环链表的长度void Print_DSCriculist(DSCriculist &L);//以此输出双向循环链表的数据域的值//函数定义部分void Error(char *s) //错误处理函数{	cout << s << endl;	exit(1);} DSCriculist *Creat_DSCriculist(){	DSCriculist *head, *tail, *ptr;	int length = 0;	int number = 0;	head = (struct DSCriculist*)malloc(LEN);	if (NULL == head)		Error("内存分配失败！");	head->data = 0;	head->next = head;	head->prior = head;	tail = head;	cout << "请输入链表长度：";	cin >> length;	cout << "请输入链表数据：" << endl;	for (int i = 0; i < length; i++)	{		ptr = (struct DSCriculist*)malloc(LEN);		if (NULL == ptr)			Error("内存分配失败！");		cin >> number;		ptr->data = number;		tail->next = ptr;		ptr->prior = tail;		ptr->next = head;		head->prior = ptr;		tail = ptr;	}	cout << "双向链表创建成功！" << endl;	return head;} DSCriculist *Find_DSCriculist(DSCriculist & L, int i){	DSCriculist *prev = L.next;	int j = 1;	while ((prev != &L) && (j < i))	{		prev = prev->next;		j++;	}	return prev;} void Insert_DSCriculist(DSCriculist & L, int i, int e){	DSCriculist *prev = Find_DSCriculist(L, i);	DSCriculist *ptr = (struct DSCriculist*)malloc(LEN);	if (NULL == ptr)		Error("内存分配失败！");	ptr->data = e;	prev->prior->next = ptr;	ptr->next = prev;	prev->prior = ptr;	ptr->prior = prev->prior;}void Delete_DSCriculist(DSCriculist & L, int i, int e)//删除双向循环链表中第i个结点，并用e返回该结点数据域的值{	DSCriculist *prev = Find_DSCriculist(L, i);	e = prev->data;	if (prev->next == &L)	{		DSCriculist *pt = prev->prior;		pt->next = &L;	}	else	{		prev->prior->next = prev->next;		prev->next->prior = prev->prior;	}	cout << "删除的元素是：" << e << endl;;	delete prev;}void Search_DSCriculist(DSCriculist &L, int e)//查找双向循环链表中数据域为e的结点，并输出该节点的位置{	DSCriculist *prev = L.next;	if (prev == &L)		Error("位置错误!");	int k = 1;	while ((prev->next != &L) && (prev->data != e))	{		prev = prev->next;		k++;	}	cout << "该元素在链表中的位置是：" << k << endl;} int Getlength_DSCriculist(DSCriculist & L){	DSCriculist *prev = &L;	int length = 0;	while (prev->next != &L)	{		prev = prev->next;		length++;	}	return length;}void Print_DSCriculist(DSCriculist &L){	DSCriculist *prev = L.next;	if (prev == &L)		Error("该链表为空表!");	cout << "该链表数据是：" << endl;	while (prev->next!= &L)	{		cout << prev->data << " ";		prev = prev->next;	}	cout << endl;} int main(){	DSCriculist *p = NULL;	int m, n, t, q;	int e = 0;	p = Creat_DSCriculist();	Print_DSCriculist(*p);	cout << "该链表的长度是：" << Getlength_DSCriculist(*p) << endl;	cout << "请输入你要插入的位置：";	cin >> m;	cout << "请输入你要插入的元素：";	cin >> n;	Insert_DSCriculist(*p, m, n);	Print_DSCriculist(*p);	cout << "插入后的链表的长度是：" << Getlength_DSCriculist(*p) << endl;		cout << "请输入你要删除的位置：";	cin >> q;	Delete_DSCriculist(*p, q, e);	Print_DSCriculist(*p);	cout << "删除后的链表的长度是：" << Getlength_DSCriculist(*p) << endl;	cout << "请输入要查找的元素：";	cin >> t;	Search_DSCriculist(*p, t);	return 0;}