CODEWITHSUNDEEP
c++templates
A. K.
A. K.

Reputation: 38214

template specialization of class Stack

I want to write two different implementations of class Stack.

(1) 

template<typename element_type, typename container_type = std::vector<element_type> >
   class Stack{//...

    };

(2)

template<typename element_type, size_t container_size>
   class Stack{
   };

If I define both the implementations in a single file I get compiler error. Is it possible to have both of them in the same file?

//compiler errors:

Stack.hpp:119:46: error: declaration of template ‘template<class element_type, long unsigned int container_size> int containers::Stack()’
Stack.hpp:25:9: error: conflicts with previous declaration ‘template<class element_type, class container_type> class containers::Stack’
Stack.hpp:25:9: error: previous non-function declaration ‘template<class element_type, class container_type> class containers::Stack’
Stack.hpp:119:46: error: conflicts with function declaration ‘template<class element_type, long unsigned int container_size> int containers::Stack()’

Upvotes: 0

Views: 165

Answers (3)

Fozi
Fozi

Reputation: 5135

You have to write something like this:

template<typename element_type, typename container_type = std::vector<element_type> >
class Stack {
  // This is *not* the specialization
};

template<typename element_type>
class Stack<element_type, std::vector<element_type> > {
  // Specialization goes here.
};

Edit: You can't change the type of the template parameter.

Upvotes: 2

AardvarkSoup
AardvarkSoup

Reputation: 1081

Nope, you can't. You can't have two versions of a templated class with different template parameters. I recommend calling the two kinds of Stack differently or putting them in different namespaces.

Upvotes: 3

Vaughn Cato
Vaughn Cato

Reputation: 64308

You have to give them two different names if they take different kinds of parameters.

Upvotes: 1

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