#include <functional>
#include <type_traits>
int main()
{
static_assert((!std::is_base_of<std::unary_function <int, int>,
std::function<int()> >::value), "");
static_assert((!std::is_base_of<std::binary_function<int, int, int>,
std::function<int()> >::value), "");
static_assert(( std::is_same< std::function<int()>::result_type,
int>::value), "");
static_assert(( std::is_base_of<std::unary_function <int, double>,
std::function<double(int)> >::value), "");
static_assert((!std::is_base_of<std::binary_function<int, int, double>,
std::function<double(int)> >::value), "");
static_assert(( std::is_same< std::function<double(int)>::result_type,
double>::value), "");
static_assert((!std::is_base_of<std::unary_function <int, double>,
std::function<double(int, char)> >::value), "");
static_assert(( std::is_base_of<std::binary_function<int, char, double>,
std::function<double(int, char)> >::value), "");
static_assert(( std::is_same< std::function<double(int, char)>::result_type,
double>::value), "");
}