用GUID方法判断指向类的指针是否被释放

/ Ex_1.cpp : 定义?控?制?台应|用?程序的?入?口点?。/#include stdafx.h#include #include /用?GUID，?判D断?指?针?是?否?被?释放?const GUID IID_CommMsgLink = 0xdeb9c823, 0x6350, 0x45a9, 0x88, 0xb9, 0x83, 0xa6, 0xd4, 0xf1, 0x8c, 0xf4 ;const GUID IID_B = 0xdeb9c723, 0x4350, 0x45a9, 0x88, 0xb9, 0x83, 0xa6, 0xd4, 0xf1, 0x8c, 0xf4 ;using namespace std;class Shapepublic:GUID IID_COMMMSGLINK;Shape()IID_COMMMSGLINK = IID_CommMsgLink;Shape()IID_COMMMSGLINK = GUID_NULL;virtual double CalLength()return 2*(nWidth+nLength);private:virtual double CalArea()return nWidth*nLength;int nWidth;int nLength;class Square:public Shapepublic:Square(int width,int length)nWidth = width;nLength = length;private:virtual double CalArea()return nWidth*nLength;int nWidth;int nLength;class Bpublic:GUID GUID_B;B()GUID_B = IID_B;B()GUID_B = GUID_NULL; /赋值为空;/判断指针是否被释放static BOOL IsPtrErr(const GUID& cid, DWORD_PTR* ptr)_tryif (cid = *(GUID*)(ptr)return FALSE;elsereturn TRUE;_except(EXCEPTION_EXECUTE_HANDLER)return TRUE;int _tmain(int argc, _TCHAR* argv)Shape* p = new Shape;/由于有虚函数这里的指针位置得加1BOOL bIsErr = IsPtrErr(IID_CommMsgLink,(DWORD_PTR*)p+1);coutbIsErrendl;delete p;/加上?虚函数y指?针?的?长度bIsErr = IsPtrErr(IID_CommMsgLink,(DWORD_PTR*)p+1);coutbIsErrendl;cout-n;B* pB = new B;/由于不?存?在虚函数y ，?不?用?加上?虚函数y的?指?针?bIsErr = IsPtrErr(IID_B,(DWORD_PTR*)pB);coutbIsErrendl;delet