C++ compile problem

I have a compile problem here.
I have a vector declared as:

Code:

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std::vector<CGameObject> _vGameObjects;

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CGameObject is an abstract class.

Code:

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_vGameObjects.push_back(_paddle);

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In the code above I want to push a _paddle object, which is an instance of a concrete object derived from the CGameObject.
The compiler (VC++ 6.0) generates an error and a series of warnings:

c:\program files\microsoft visual studio\vc98\include\xmemory(34) : error C2259: 'CGameObject' : cannot instantiate abstract class due to following members:
f:\projects\simple game\game1\src\cgameobject.h(33) : see declaration of 'CGameObject'
c:\program files\microsoft visual studio\vc98\include\xmemory(66) : see reference to function template instantiation 'void __cdecl std::_Construct(class CGameObject *,const class CGameObject &)' being compiled
c:\program files\microsoft visual studio\vc98\include\xmemory(34) : warning C4259: 'void __thiscall CGameObject::InitBoundingBoxes(void)' : pure virtual function was not defined
f:\projects\simple game\game1\src\cgameobject.h(51) : see declaration of 'InitBoundingBoxes'
c:\program files\microsoft visual studio\vc98\include\xmemory(66) : see reference to function template instantiation 'void __cdecl std::_Construct(class CGameObject *,const class CGameObject &)' being compiled
c:\program files\microsoft visual studio\vc98\include\xmemory(34) : warning C4259: 'class std::vector<struct BBox,class std::allocator<struct BBox> > &__thiscall CGameObject::BoundingBoxes(void)' : pure virtual function was not defined
f:\projects\simple game\game1\src\cgameobject.h(59) : see declaration of 'BoundingBoxes'
c:\program files\microsoft visual studio\vc98\include\xmemory(66) : see reference to function template instantiation 'void __cdecl std::_Construct(class CGameObject *,const class CGameObject &)' being compiled
c:\program files\microsoft visual studio\vc98\include\xmemory(34) : error C2259: 'CGameObject' : cannot instantiate abstract class due to following members:
f:\projects\simple game\game1\src\cgameobject.h(33) : see declaration of 'CGameObject'
c:\program files\microsoft visual studio\vc98\include\xmemory(66) : see reference to function template instantiation 'void __cdecl std::_Construct(class CGameObject *,const class CGameObject &)' being compiled
c:\program files\microsoft visual studio\vc98\include\xmemory(34) : warning C4259: 'void __thiscall CGameObject::InitBoundingBoxes(void)' : pure virtual function was not defined
f:\projects\simple game\game1\src\cgameobject.h(51) : see declaration of 'InitBoundingBoxes'
c:\program files\microsoft visual studio\vc98\include\xmemory(66) : see reference to function template instantiation 'void __cdecl std::_Construct(class CGameObject *,const class CGameObject &)' being compiled
c:\program files\microsoft visual studio\vc98\include\xmemory(34) : warning C4259: 'class std::vector<struct BBox,class std::allocator<struct BBox> > &__thiscall CGameObject::BoundingBoxes(void)' : pure virtual function was not defined
f:\projects\simple game\game1\src\cgameobject.h(59) : see declaration of 'BoundingBoxes'
c:\program files\microsoft visual studio\vc98\include\xmemory(66) : see reference to function template instantiation 'void __cdecl std::_Construct(class CGameObject *,const class CGameObject &)' being compiled


Any suggestions? Thanks!

Make sure you define all your abstract methods somewhere, and you could use a vector of pointers to CGameObject rather than the objects themeselves as the vector implementation is probably trying to call the abstract constructor.

You cannot create an abstract calss object. Use pointers as Sorensen suggested

std::vector<CGameObject*> _vGameObjects;

_vGameObjects->push_back(_paddle);

Thanks to both of you!

I was wondering if I could use references instead of pointers. Is there any significative difference?

... on a second thought, it does not compile if I try using references... the pointer solution just works :)