Re: Is this legal C++?

arrowtackett <arrowtackett@gmail.com> writes:


I don't see a problem with the principle, but

template<typename A>
unsigned int getDimension(A const &)
{
   return 0;
}

template<typename A>
unsigned int getDimension(std::vector<A> const &vec)
{
   assert(!vec.empty());
   return getDimension(vec[0])+1;
}

is a simpler way to do it.

And this does it at compile time, which is even nicer:

#include <iostream>
#include <ostream>
#include <vector>

template <typename T>
struct vectorDimension
{
     enum
     {
       value = 0
     };
};

template <typename T>
struct vectorDimension< std::vector<T> >
{
     enum
     {
       value = vectorDimension<T>::value+1
     };
};

int main()
{
   typedef std::vector<double> V1;
   typedef std::vector<std::vector<double> > V2;
   typedef std::vector<std::vector<std::vector<double> > > V3;

   std::cout << "The dimension of the vector is: "
             << vectorDimension<V3>::value
             << '\n';
}

--
      [ See http://www.gotw.ca/resources/clcm.htm for info about ]
      [ comp.lang.c++.moderated. First time posters: Do this! ]