双链表反序（链表）

Every storm is part of your journey. 

Yes, you will make it through this one too. You will come out stronger than you were 

before...      

双链表定义

typedef struct _dNode
{
    int data;
    struct _dNode *pre;
    struct _dNode *next;
}DNode;      

关键点

1.关键在于节点中的pre, next指针，只要交换他们的值，就可以将双链表反序。

int ReverseDoubleList(DNode * h)
{
    if(!h || !h->next) {
        printf("DLinkedNode:Reverse！\n");
        return -1;
    }
    
    DNode *p,*temp;
    p=h->next;
    while(p!=NULL) {
        temp=p->pre;
        p->pre=p->next;
        p->next=temp;
 
        if(p->pre==NULL)
            break;
        else
            p=p->pre;
    }
    
    h->next->next=NULL;
    h->next=p;
    return 0;
}