循环双向链表的基本操作

#include <iostream>
#include <cstdio>
#include <stdlib.h>
using namespace std;
typedef int ElemType;
typedef struct DulNode
{
    ElemType data;
    struct DulNode *prior;
    struct DulNode *next;
}DulNode,*DuLinkList;
DuLinkList CreateDuLinkList(int n)
{
    int x;
    DulNode *h,*p;
    h=(DulNode *)malloc(sizeof(DulNode));
    h->next = h;
    h->prior = h;
    p=h;
    printf("输入元素：");
    while(n--)
    {
        scanf("%d",&x);
        DulNode *l;
        l=(DulNode *)malloc(sizeof(DulNode));
        l->data=x;
        p->next=l;
        l->prior=p;
        l->next = h;//l->next指向头结点
        h->prior = l;
        p=l;
    }
    return h;
}
void output(DuLinkList L)
{
    DulNode *p;
    for(p=L->next;p->next!=L->next;p=p->next)//终止条件为p->next不为头结点
    {
        printf("%d ",p->data);
    }

}
void InsertDuLinkedList(DuLinkList L,int i,ElemType e)
{
    int j;
    DuLinkList p;
    p=L;
    j=1;
    while(j<i)
    {
        p=p->next;
        j++;
    }
    DulNode *s;
    s=(DulNode *)malloc(sizeof(DulNode));
    s->data = e;
    s->prior = p;
    p->next->prior = s;
    s->next = p->next;
    p->next = s;

}
void DeleteDuLinkList(DuLinkList L,int i)
{
    int j;
    DuLinkList p;
    p=L;
    j=1;
    while(j<=i)
    {
        p=p->next;
        j++;
    }
    p->prior->next = p->next;
    p->next = p->prior;
    free(p);

}
int CountDuLinkList(DuLinkList L)
{
    int count=0;
    DuLinkList p;
    p=L;
    while(p->next!=L)
    {
        count++;
        p=p->next;
    }
    return count;
}
int main()
{
    int n,i,x;
    DuLinkList L;
    printf("输入要创建的循环双向链表的长度：");
    scanf("%d",&n);
    L=CreateDuLinkList(n);
    output(L);
    printf("\n输入要插入的节点的位置和元素：");
    scanf("%d %d",&i,&x);
    InsertDuLinkedList(L,i,x);
    output(L);
    printf("\n输入要删除哪一位置上的元素：");
    scanf("%d",&i);
    DeleteDuLinkList(L,i);
    output(L);
    printf("\n当前链表的长度为%d",CountDuLinkList(L));
    return 0;
}