数据结构学习笔记-13

#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 InitLisk(DuLinkList *L)
{
        DualNode *p, *q;
        int i;

        *L = (DuLinkList)malloc(sizeof(DualNode));

        if( !(*L) )
        {
            return ERROR;
        }

    (*L)->next = (*L)->prior = 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;

    return OK;
}

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

    if(i < 0 )
    {

        i=i-1;
        (*L)=(*L)->next;

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

    }
}

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

    InitLisk(&L);
    printf("请输入一个整数: ");
    scanf("%d", &n);


    Caesar(&L, n);

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

    return 0;
}