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problem with templates and class constructors?

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Started by thedodgeruk June 09, 2011 09:52 PM

3 comments, last by thedodgeruk 12 years, 10 months ago

thedodgeruk

124

Author

June 09, 2011 09:52 PM

i can get this to work

#include "ttt.h"





template <class T>	



CModel* CreateInstanceCModel(T())							       //

{				

	CModel*  tempModel = new T();   	

    m_modelList.Push_Back(tempModel);



	return  tempModel;



}								       //





CreateInstanceCModel(ttt( ));

but i would like a contructor in ttt
but no matter how i code the template i cant get it to work , any ideaas?

Brother Bob

10,350

June 09, 2011 10:37 PM

What is it you're trying to do? What is the template type supposed to represent? What are you doing with the parameter you pass to the function? Your question is very unclear.

Pthalicus

739

June 09, 2011 11:06 PM

It looks like you're getting confused with c++ templates here. You're creating a type T, which will be replaced by the compiler with the type you specify.
This looks like an attempt to implement a factory function for different types with a common CModel ancestor. How about simply registering a function or class to create a given CModel derivative, and then calling CreateInstanceCModel() to use the factory function and create an instance of that class.

Saving the world, one semi-colon at a time.

jonathanjansson

271

June 09, 2011 11:10 PM

Maybe something like this?

template <typename T>

CModel* CreateInstanceCModel()

{

	CModel* model = new T();

	m_modelList.push_back(model);

	return model;

}



template <typename T, typename A1>

CModel* CreateInstanceCModel(A1 const& a1)

{

	CModel* model = new T(a1);

	m_modelList.push_back(model);

	return model;

}



template <typename T, typename A1, typename A2>

CModel* CreateInstanceCModel(A1 const& a1, A2 const& a2)

{

	CModel* model = new T(a1, a2);

	m_modelList.push_back(model);

	return model;

}



// Etc...

and then

CModel* model = CreateInstanceCModel<SpecificModel>(arguments);

Capoeira Sul da Bahia Göteborg

thedodgeruk

124

Author

June 09, 2011 11:17 PM

What is it you're trying to do? What is the template type supposed to represent? What are you doing with the parameter you pass to the function? Your question is very unclear.

CModel is my base model class

i want to be able to create a class that has a base of CModel

eg Rocket , gun, player, enemy etc

and impliment it with CreateCModel(Rocket());

but would like to use constructors though in the creation off . eg Rocket(CMEsh* meshTypeUsed);

problem with templates and class constructors?

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