I am looking for an example of an iterator which satisfies the limited qualities to be considered a ForwardIterator, while not being anything else in the hierarchy of iterators.
I have written a program which prints which of the five iterator categories an iterator conforms to. I have tested it for the other four iterator categories.
A typical example is std::forward_list<T>::iterator. Testing snippet:
#include <iostream>
#include <iterator>
#include <forward_list>
#include <vector>
template<typename T>
bool test = std::is_same <
typename std::iterator_traits <
typename T::iterator
>::iterator_category,
std::forward_iterator_tag
>::value ;
int main()
{
// test wheter std::forward_list's iterator is a forward_iterator
std::cout << std::boolalpha << test<std::forward_list<int>> << std::endl;
// what about std::vector?
std::cout << std::boolalpha << test<std::vector<int>>;
}