双向链表元素的删除

struct Node 
{
    int Data;
    struct Node* prior;
    struct Node* next;
};

/**           
* @brief 该函数实现了删除带头结点双链表中第i个结点  
* @param[in] head 待删除结点链表       
* @param[in] i 待删除结点位置
* @param[out] e 删除结点内容
* @notice 带头结点的双链表中第一个元素为头结点后的元素，所以不存在删除头结点的情况

* @author [e-mail]         
*      http://blog.csdn.net/rabbit729        
* @version 1.0          
* @date 2009-03-09       
*/ 
int DelDoubleList(Node* head, const int i, int& e)
{
    assert(head);

    if (head->next == NULL)
    {
        return -1;
    }
    Node* p = head;
    int j = 0;

    // 寻找待删除结点
    while ((p->next != NULL) && (j < i))
    {
        p = p->next;
        j++;
    }

    // 处理删除最后一个结点的情况
    if (p->next == NULL)
    {
        e = p->Data;
        p->prior->next = NULL;
        delete p;
        p = NULL;
        return 0;
    }
    else
    {
        e = p->Data;

        p->next->prior = p->prior;
        p->prior->next = p->next;
        delete p;
        p = NULL;
        return 0;
    }
}

/**           
* @brief 该函数实现了删除带头结点双链表中与给定值相等的第一个结点  
* @param[in] head 待删除结点链表       
* @param[in] data 待删除结点元素值

* @author [e-mail]         
*      http://blog.csdn.net/rabbit729        
* @version 1.0          
* @date 2009-03-09       
*/ 
int DelDoubleList(Node* head, int data)
{
    assert(head);
    if (head->next == NULL)
    {
        return -1;
    }

    Node* prior = head;
    Node* q = head->next;

    // 寻找待删除结点
    while((q != NULL) && (q->Data != data))
    {
        q = q->next;
    }

    // 删除元素
    if ((q != NULL) && (q->Data == data))
    {
        // 处理删除最后一个结点的情况
        if (q->next == NULL)
        {
            q->prior->next = NULL;
            delete q;
            q = NULL;
            return 0;
        }
        else
        {
            q->next->prior = q->prior;
            q->prior->next = q->next;
            delete q;
            q = NULL;
            return 0;
        }
    }
    else
    {
        cout<<"Could not find data!"<<endl;
        return -1;
    }
}