struct ListNode {	 int val;	 ListNode *next;	 ListNode(int x) : val(x), next(NULL) {} }; void createList(ListNode* &pHead){	 pHead = new ListNode(-1);	 int length = 5;	 ListNode *p = pHead;	 for (size_t i = 0; i < length; i++)	 {		 ListNode *node = new ListNode(i);		 p->next = node;		 p = node;	 }		 } void destroyList(ListNode* pHead){	 _ASSERT(pHead != NULL);	 ListNode *pNext = pHead->next;	 while (pNext!=NULL)	 {		 delete pHead;		 pHead = pNext;		 pNext = pHead->next;	 };	 delete pHead;	 pHead = NULL;	  }