RE: [Dev-C++] C++ Virtual function Tables and Implementation - Complet ed Code listing

[<eng...@ju...>]

Hi,

I'm sorry for not showing all of the code. Here it is:


  class InternetConnection { 
public: 
............virtual int iconnect(...) =0; //Pure Virtual Method
};
class DSLConnection : public InternetConnection {
public:
............virtual int iconnect(...); //definition not shown
}; 
class ISDNConnection : public InternetConnection {
public:
............virtual int iconnect(...); //definition not shown
} 
class DailupConnection : public InternetConnection {
public:
............. virtual int iconnect(...); //definition not shown
};
//////////////////////////////////////////////////////////////////////
////This class is not derived from InternetConnection
//////////////////////////////////////////////////////////////////////
class ExportedConnection {
public:
.........virtual int iconnect(...); //definition not shown
};
 
int main() {

InternetConnection *ic = new DSLConnection; //Derived from InternetConnection 

InternetConnection *ic2 = new DailupConnection; //Derived from InternetConnection 

ExportedConnection exported_object; //Not Derived from InternetConnection 


ic->iconnect();
ic2->iconnect();

delete ic;
delete ic2;

//The cast to void* then assignment
(void*)ic=&exported_object; //Virtual function table pointer assignment via cast to void*

ic->iconnect(); //exported_object's method called

return 0;
} 

This compiles on Linux using g++,  Borland C++ and works with Borland Delphi and Borland C++ class objects. The VC++ compiler is implemented differently so Borland and VC++ objects might not work.


Thanks,

Jim E. Smith


________________________________________________________________
The best thing to hit the Internet in years - Juno SpeedBand!
Surf the Web up to FIVE TIMES FASTER!
Only $14.95/ month - visit www.juno.com to sign up today!