两种方法（递归，非递归）实现单链表的逆转

//普通方法实现链表的逆置
void reverseList(pNode *head)
{
pNode p, q, r;
if (*head == NULL || (*head)->next == NULL)
return;
q = *head;
p = q->next;
r = NULL;
while (p){
q->next = r;
r = q;
q = p;
p = p->next;
}
q->next = r;
*head = q;
}

//递归法实现链表的逆置
pNode reverseList_reverse(pNode head)
{
pNode current_head, head_next;
if (head == NULL)
return NULL;

if (head->next == NULL)//边界条件
return head;
else{
current_head = head;//记下当前的头结点a0
head_next = head->next;//记下当前头结点后面的结点a1
head = reverseList_reverse(head_next);//返回(a1...an)逆转后的头结点
head_next->next = current_head;//用上面保存的地址（逆转后的尾结点）指向原来的头结点a0
current_head->next = NULL;//将a0的next域置零
}
return head;//返回a0
}