Template Base Class with Factories

Wed, 28 Jan 2009 09:18:51 -0800 (PST)
Hi, I'm going to use a simplified example to ask my question.

Suppose I have a base class:

template <class T> class BaseClass {

with a couple of classes which inherit it

class Example1 : public BaseClass<int> {

class Example2 : public BaseClass<float> {

Question: How do I write a Factory class to return a reference to
BaseClass? Such as:

class FactoryClass {

          template <class T> BaseClass<T> *Create(int option) {
                                 switch (option) {
                                     case 0 : return(new Example1);
                                     case 1: return(new Example2);

Where in my code I would call it as such.....

  FactoryClass thisFactory;
  BaseClass<???> *thisBaseClass1 = thisFactory.Create(0);
  BaseClass<???> *thisBaseClass2 = thisFactory.Create(1);

Now, I know that BaseClass is defined with a template parameter, but
in this case I do not know what that parameter is until the factory
creates it. Is there a way to define the local reference to BaseClass
in the code such that "I don't know what the type is and I don't care
at this point"? Go easy on me, I'm relatively new to templates.



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