Linear table - two-way circular list

1, two-way circular list

Doubly linked list in a single list for each node, and then its precursor is provided a carton node pointer field. Doubly linked list can effectively improve the time performance of the algorithm, using space for time.

typedef struct the Node 
{ 
    elemType Data; 
    struct the Node * Prior;     // immediate predecessor pointers 
    struct the Node * Next;     // immediate successor pointers 
} Node, * CLinkList;

2, a doubly linked list insertion order :( Note)

s->next=p;
s->prior=p->prior;
p->prior->next=s;
p->prior=s;

Delete node:

p->prior->next=p->next;
p->next->prior=p->prior;
free(p);

3, example:

#include <stdio.h>
#include <stdlib.h>

#define OK 1
#define ERROR 0

typedef char ElemType;
typedef int  Status;

typedef struct DualNode
{
    ElemType data;
    struct DualNode* prior;
    struct DualNode* next;
}DualNode, *DuLinkList;

Status InitList(DuLinkList *L)
{
    DualNode *p, *q;
    int i;

    *L = (DuLinkList)malloc(sizeof(DualNode));
    if (!(*L))
    {
        return ERROR;
    }
    (*L)->prior = (*L)->next = NULL;
    p = (*L);

    for (i = 0; i < 26; i++)
    {
        q = (DualNode*)malloc(sizeof(DualNode));
        if (!q)
        {
            return ERROR;
        }
        q->data = 'A' + i;
        q->prior = p;
        q->next = p->next;
        p->next = q;

        p = q;
    }
    p->next = (*L)->next;
    (*L)->next->prior = p;
    (*L)->prior = p->prior;
    return OK;
}

void Caesar(DuLinkList* L, int i)
{
    if (i > 0)
    {
        do 
        {
            (*L) = (*L)->next;
        } while (--i);
    }

    if (i < 0)
    {
        do
        {
            (*L) = (*L)->prior;
        } while (++i);
    }
}

int main()
{
    DuLinkList L;
    int i,n;

    InitList(&L);
    printf("请输入一个整数：");
    scanf_s("%d", &n);
    printf("\n");
    Caesar(&L, n);

    for (i = 0; i < 26; i++)
    {
        L = L->next;
        printf("%c", (L)->data);
    }
    printf("\n");
    return 0;
}