Re: template template parameters not working with STL containers

From:
red floyd <redfloyd@gmail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
Thu, 19 Feb 2009 01:13:33 CST
Message-ID:
<0ccadb2c-b75b-431a-b2ab-b5d82aba6ffe@m2g2000vbp.googlegroups.com>
On Feb 18, 5:26 am, vl106 <vl...@hotmail.com> wrote:

The code sample below is not working. It is taken from
Nicolai Josuttis "C++ Templates: The Complete Guide".
In the chapter 5.4 Template Template Parameters it reads
[slightly stripped]:

#include <deque>

template <typename T>
class MyVector {
public:
        void push_back(T const&) {}

};

template <typename T, template <typename> class CONT = /*MyVector*/
std::deque >
class Stack {
private:
     CONT<T> elems; // elements
   public:
     void push(T const&); // push element

};

template <typename T, template <typename> class CONT>
void Stack<T,CONT>::push(T const& elem)
{
     elems.push_back(elem); // append copy of passed elem

}

int main() {
        Stack<int> iStack;
        iStack.push(1);
        return 0;

}

With Visual Studio 2005 I get the following error message:

  error C3201: the template parameter list for class template
'std::deque' does not match the template parameter list for template
parameter 'CONT'
  error C3201: the template parameter list for class template
'std::deque' does not match the template parameter list for template
parameter 'CONT'
  error C2976: 'std::deque' : too few template arguments
  deque(486) : see declaration of 'std::deque'

The problems is not the template template parameter itself.
When I substitute the default argument with "MyVector" the
code compiles fine.

How do I have to modify the sample to make it work with the
original STL containers std::deque, std::vector, ...


std::deque has *two* template parameters. Therefore it doesn't match
your template template class parameter.

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