[RESOLVED] Issue with ABCs - ERROR C2259

[Lapin]

Hi,

I am getting trouble to make my ABC working.

I can not compile my dll as soon as I use an ABC. The compiler tells me error C2259: 'xlINSTRUMENTS' : cannot instantiate abstract class

I have searched around and I thought it was a signature problem but it does not look like since the 2 functions are really the same.

I thouth also it was a problem of object creation but it is unlikely also.
In order to create my xlMM object, I write the following line:

xlINSTRUMENTS * abc = new xlMM(..........);
with xlMM(..........) being the correct constructor.

or xlINSTRUMENTS abc = xlMM( ..... ) if I want to create the object it self and not a pointer.

I am under Visual studio .NET 2003 and I am trying to compile a Multithreaded dll.
I have enclosed the code at the end in order to be complete.

Any help would be greatly appreciated.
Lapin

//Abstract class definition

class xlINSTRUMENTS
{
private:
std::string Name;
public:
virtual double RetrieveInstrument( const double & ,const double & ) const = 0 ;

}

//Derived class definition

class xlMMublic xlINSTRUMENTS
{
private:
...
public:
virtual double RetrieveInstrument(const double & ,const double & ) const ;
};

//virtual fonction definition
double xlMM::RetrieveInstrument( const double &InputHeader ,const double &InputValue ) const
{
return InputHeader;
};

[AlanGRutter]

An ABC acts solely as a base class for inherited classes. You cannot instantiate an ABC - you must instantiate one of the derived classes using new and assign it to a pointer to the base ABC.

xlINSTRUMENTS *pABC = new xlMM(...);

Regards
Alan

[Lapin]

Thanks Alan.

I should have thought a little bit longer.
Anyway case solved.