Determine if a (c++) iterator is reverse

Question

I want a mechanism to determine in compile time whether an iterator is reverse or not.

Iterator traits can only help with the category of an iterat

Answer 1

A simple method. It is easy to use and can determine if something is a reverse iterator or not, and can differentiate between const reverse iterators if needed.

#include 

template
using IsRegRevIter = std::is_same;

template
using IsConstRevIter = std::is_same;

template
struct IsRevIter
{
     const static bool value = IsRegRevIter::value
          || IsConstRevIter::value;
};

int main()
{
     using Container = std::list;
     Container myList = {1,2,3,4,5,6};

     auto RI = myList.rbegin();
     auto I = myList.begin();

     std::cout << std::endl << std::boolalpha << IsRevIter::value; //true
     std::cout << std::endl << std::boolalpha << IsRegRevIter::value; //true
     std::cout << std::endl << std::boolalpha << IsConstRevIter::value; //false (it is not const).
     std::cout << std::endl << std::boolalpha << IsRevIter::value; //false

return 0;

}

output:
false
true
false
false