Re: template template parameters not working with STL containers
vl106 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
};
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, ...
The error messages actually tells you what the problem is:
The problem is that std::deque and std::vector also has additional
default template arguments. You require a template with a single
argument, so the standard containters do not match.
Bo Persson
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