005 -- DuLinkList_add nodes, delete node, Caser print..

000-- define a Dulinklist

A empty DuLinklist:

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

•  Add a new Node

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

• Delete a Node

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

 print A-Z with the defined sequence by user

e.g.  user input 3

then should be DEFG....ZABC

user input -3

then should be XYZABCEFG.....W

#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)->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; //the last Node points to the first Node
    (*L)->next->prior = p; //set the first Node with data 'A' as head Node
    
    return OK;
}


void caser(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;
    InitList(&L);
    printf("Please input a integer: 
");
    scanf("%d", &n);
    printf("
");
    
    caser(&L,n);
    
    for(i=0;i<26;i++)
    {
        L = L->next;
        printf("%c", L->data);
        
    }
    
    printf("
");
    
    return 0;
}