Re: Is it possible to use type traits as a template parameter?
Raider wrote:
I'm trying to create a base class who will contain generic algoritms
and derived class(es) who will perform problem-specific things. I'm
unable to use dynamic polymorphism, because base class know nothing
about problem-specific types. I wrote the following code using static
polymorphism, but compiler do not allow me to use type traits as a
template parameter, the following code not compiles:
Of course it doesn't. It's missing some vital portions:
#include <vector>
#include <iostream>
template <class CT>
struct InfoClass
{
int id;
CT content;
};
template <class T, class TTraits>
struct SomeImpl
{
void go()
{
T *pT = static_cast<T*>(this);
pT->go_implementation();
}
void set_pointer(TTraits::ptrtype newptr)
void set_pointer(typename TTraits::ptrtype newptr)
{
ptr = newptr;
}
typedef InfoClass<TTraits::basetype> obj_type;
typedef InfoClass<typename TTraits::basetype> obj_type;
std::vector<obj_type> v;
TTraits::ptrtype ptr;
typename TTraits::ptrtype ptr;
};
struct SomeClassTraits
{
typedef int basetype;
typedef char* ptrtype;
};
struct SomeClass : public SomeImpl<SomeClass, SomeClassTraits>
{
void go_implementation()
{
cout << "SomeClass.go()" << endl;
std::cout << "SomeClass.go()" << std::endl;
// use ptr as a char*
// use v as a vector<InfoClass<int> >
}
};
void TestTemplateImpl()
{
SomeClass x;
x.go();
}
[...]
Are there any possibilities to pass type traits to template as a
single argument?
I think you need to learn about "dependent names".
V
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