#include <iostream> 
#include <cstdlib>
using namespace std;
const int flag = -1;
typedef struct SiLinkCirList{
	int data;
	struct SiLinkCirList *next, *prior;
}*List;
//创建单向循环链表
void creSiLinkCirList(List &L){//system("pause");
	int x;
	L = (List)malloc(sizeof(SiLinkCirList));
	List r = L;
	while(cin>>x && x!=flag){
		List s = (List)malloc(sizeof(SiLinkCirList));
		s->data = x;
		r->next = s;
		r = s;
	}
	r->next = L;
}
//输出单向循环链表
void printSiCirList(List L){
	List p = L->next;
	cout << "当前的单向循环链表为：";
	while(p != L){
		cout << p->data << " ";
		p = p->next;
	}
	cout << endl;
}
//转换成双向循环链表
void trDouCirList(List &L) {
	List p = L;
	List s;
	while(1){
		s = p->next;
		s->prior = p;
		if(p->next==L)
			break;
		p = p->next;
	}
	L->prior = p;	
}
//根据prior输出链表
void printByPrior(List L) {
	List p = L->prior;
	cout << "反向输出的循环链表为：" ;
	while(p != L){
		cout << p->data << " ";
		p = p->prior;
	}
	cout << endl;
}
int main(){
	List L;
	cout << "输入单向循环链表元素：";
	creSiLinkCirList(L);
	printSiCirList(L);
	trDouCirList(L);
	printByPrior(L);
	return 0;
}