typedef struct _node{
    int value;
    struct _node *next;
    struct _node *prev; //previous
}Node;

int main(int argc, char const *argv[])  
{
    //input number
    int number;
    Node *head = NULL;
    Node *rlast; //reallast
    do
    {
        scanf("%d", &number);
        if(number != -1)
        {
            Node *p = (Node*)malloc(sizeof(Node));
            p->value = number;
            p->next = NULL;
            p->prev = NULL;
            
            //find the last
            Node *last = head;
            if(last)
            {
                while(last->next)
                {
                    last = last->next;
                }
                p->prev = last;
                last->next = p;
            }
            else
            head = p;
            rlast = p;
            printf("%p %p ", rlast, p); //发现rlast和p的地址一样，每次都重新申请p，之前的p空间占着不用了（没free）？
        }
    }while(number != -1);
   
    //output number
    Node *a;
    for(a = rlast;a;a = a->prev)
    {
        printf("%d ", a->value);
    }
   
    return 0;
}

[此贴子已经被作者于2016-12-14 22:31编辑过]

懂了

恩，谢谢

每个p都有存放数据，不用free