段错误一般发生在递归导致的栈溢出或这数组溢出，还有就是if语句中可能出错，比如一个链表结构：
struct ListNode {int val;struct ListNode *next;ListNode(int x) :val(x), next(NULL) {}
};且看下面代码：
ListNode* deleteDuplication(ListNode* pHead)
{ListNode *pFront=NULL, *pBack=pHead, *pMiddle = NULL;while(pBack!=NULL){pMiddle = pBack;pBack=pBack->next;if(pBack!=NULL && pBack->val==pMiddle->val){while(pBack->val==pMiddle->val){ListNode *pTemp;pTemp = pBack;pBack = pBack->next;delete pTemp;}delete pMiddle;pMiddle = NULL;if(pFront!=NULL)