Having trouble storing a CRTP based class in a vector
- by user366834
Hi,
Im not sure if this can be done, im just delving into templates so perhaps my understanding is a bit wrong.
I have a Platoon of soldiers, the platoon inherits from a formation to pick up the formations properties, but because i could have as many formations as i can think of I chose to use the CRTP to create the formations, hoping that i could make a vector or array of Platoon to store the platoons in. but, of course, when i make a Platoon, it wont store it in the vector, "types are unrelated"
Is there any way around this ? i read about "Veneers" which are similar and that they work with arrays but i cant get it to work, perhaps im missing something.
here's some code: (sorry about the formatting, the code is here in my post but its not showing up for some reason )
template < class TBase >
class IFormation
{
public :
~IFormation(){}
bool IsFull()
{
return m_uiMaxMembers == m_uiCurrentMemCount;
}
protected:
unsigned int m_uiCurrentMemCount;
unsigned int m_uiMaxMembers;
IFormation( unsigned int _uiMaxMembers ): m_uiMaxMembers( _uiMaxMembers ), m_uiCurrentMemCount( 0 ){} // only allow use as a base class.
void SetupFormation( std::vector<MySoldier*>& _soldierList ){}; // must be implemented in derived class
};
/////////////////////////////////////////////////////////////////////////////////
// PHALANX FORMATION
class Phalanx : public IFormation<Phalanx>
{
public:
Phalanx( ):
IFormation( 12 ),
m_fDistance( 4.0f )
{}
~Phalanx(){}
protected:
float m_fDistance; // the distance between soldiers
void SetupFormation( std::vector<MySoldier*>& _soldierList );
};
///////////////////////////////////////////////////////////////////////////////////
// COLUMN FORMATINO
class Column : public IFormation< Column >
{
public :
Column( int _numOfMembers ):
IFormation( _numOfMembers )
{}
~Column();
protected:
void SetupFormation( std::vector<MySoldier*>& _soldierList );
};
I then use these formations in the platoon class to derive, so that platoon gets the relevant SetupFormation() function:
template < class Formation >
class Platoon : public Formation
{
public:
**** platoon code here
};
everything works great and as expected up until this point.
now, as my general can have multiple platoons, I need to store the platoons.
typedef Platoon< IFormation<> > TPlatoon; // FAIL
typedef std::vector<TPlatoon*> TPlatoons;
TPlatoon m_pPlatoons
m_pPlatoons.push_back( new Platoon<Phalanx> ); // FAIL, types unrelated.
typedef Platoon< IFormation< TPlatoon; fails because i need to specify a template parameter, yet specifying this will only allow me to store platoons created with the same template parameter.
so i then created FormationBase
class FormationBase
{
public:
virtual bool IsFull() = 0;
virtual void SetupFormation( std::vector<MySoldier*>& _soldierList ) = 0;
};
and made IFormation publicly inherit from that, and then changed the typedef to
typedef Platoon< IFormation< FormationBase > > TPlatoon;
but still no love.
now in my searches i have not found info that says this is possible - or not possible.
