#include <iterator>
#include <type_traits>
struct A {};
template <class T>
void
test2()
{
typedef std::iterator<std::forward_iterator_tag, T> It;
static_assert((std::is_same<typename It::value_type, T>::value), "");
static_assert((std::is_same<typename It::difference_type, std::ptrdiff_t>::value), "");
static_assert((std::is_same<typename It::pointer, T*>::value), "");
static_assert((std::is_same<typename It::reference, T&>::value), "");
static_assert((std::is_same<typename It::iterator_category, std::forward_iterator_tag>::value), "");
}
template <class T>
void
test3()
{
typedef std::iterator<std::bidirectional_iterator_tag, T, short> It;
static_assert((std::is_same<typename It::value_type, T>::value), "");
static_assert((std::is_same<typename It::difference_type, short>::value), "");
static_assert((std::is_same<typename It::pointer, T*>::value), "");
static_assert((std::is_same<typename It::reference, T&>::value), "");
static_assert((std::is_same<typename It::iterator_category, std::bidirectional_iterator_tag>::value), "");
}
template <class T>
void
test4()
{
typedef std::iterator<std::random_access_iterator_tag, T, int, const T*> It;
static_assert((std::is_same<typename It::value_type, T>::value), "");
static_assert((std::is_same<typename It::difference_type, int>::value), "");
static_assert((std::is_same<typename It::pointer, const T*>::value), "");
static_assert((std::is_same<typename It::reference, T&>::value), "");
static_assert((std::is_same<typename It::iterator_category, std::random_access_iterator_tag>::value), "");
}
template <class T>
void
test5()
{
typedef std::iterator<std::input_iterator_tag, T, long, const T*, const T&> It;
static_assert((std::is_same<typename It::value_type, T>::value), "");
static_assert((std::is_same<typename It::difference_type, long>::value), "");
static_assert((std::is_same<typename It::pointer, const T*>::value), "");
static_assert((std::is_same<typename It::reference, const T&>::value), "");
static_assert((std::is_same<typename It::iterator_category, std::input_iterator_tag>::value), "");
}
int main()
{
test2<A>();
test3<A>();
test4<A>();
test5<A>();
}