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POIs it safe to cast this to a base-class pointer?
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copied!<p>I'm currently learning C++, and this time I was messing with pointers, and studying the <code>this</code> pointer and polymorphism. My question is, is the conversion below safe, I know that basically I can access <code>m_uConnectedUsers</code> directly from <code>CUser</code> class because of 'public', but I may find an occasion where it will be needed, and I would like to know the opinion of you professionals about it.</p> <pre><code>#include <windows.h> #include <iostream> using namespace std; class CUserCounter { public: CUserCounter(); virtual ~CUserCounter(){}; BOOL m_bEmpty; u_long m_uConnectedUsers; }; CUserCounter::CUserCounter() { m_bEmpty = TRUE; m_uConnectedUsers = 0; } class CUser : public CUserCounter { public: CUser(LPCTSTR szName, BOOL bConnected, BOOL bChatting = FALSE ); virtual ~CUser(){}; BOOL m_bConnected; BOOL m_bIsChatting; TCHAR szCharName[32]; bool IncreaseMoverMeter( unsigned uMeters ); }; CUser::CUser( LPCTSTR szName, BOOL bConnected, BOOL bChatting ) { if( szName ) { if( strlen( szName ) > 30 ) strcpy( szCharName, "Invalid" ); else strcpy( szCharName, szName ); } m_bConnected = bConnected; m_bIsChatting = bChatting; } bool CUser::IncreaseMoverMeter( unsigned uMeters ) { //is it safe? how does it works CUserCounter* pUserCounter = (CUserCounter*)this; if( pUserCounter ) { pUserCounter->m_uConnectedUsers++; return true; } return false; } int main( int argc, char *argv[] ) { CUser *pUser = new CUser( "Jonh", FALSE ); std::cout << pUser->IncreaseMoverMeter( 4 ); system("pause>nul"); return EXIT_SUCCESS; } </code></pre>

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