ListNode *listReverse(ListNode *pHead)
{
	if(pHead == NULL)
		return NULL;
	ListNode *pCurrent ,*pPre,*pNext;
		
	//一、指针的初始化阶段
	pPre = pHead;
	pCurrent = pPre->next ;

	//二、反转单链表的核心代码
	while(pCurrent)               
	{
		pNext = pCurrent->next ;   //1. 缓冲pCurrent后面的单链表
		pCurrent->next = pPre ;	   //2. 反转单链表
		pPre = pCurrent;           //3. 让pPre指针后移
		pCurrent = pNext ;         //4. 让pCurrent指针后移
	}
	
    //三、处理并返回头指针
	pHead->next = NULL;             //把原头结点的next域变成空指针
	pHead = pPre ;		           //把头结点指向最后一个结点产生新的头结点，也就是把原单链表的尾结点变成头结点

	return pHead;
}