#include <iostream>
#include <type_traits>
 
template <typename ClassType>
static std::true_type test(decltype(&ClassType::helloworld));

template <typename ClassType>
static std::false_type test(...);

struct has_helloworld_class {
	void helloworld();
};
 
struct no_helloworld_class {
};

int main () {
	using namespace std;
	
	cout << decltype(test<has_helloworld_class>(nullptr))::value << endl;
	cout << decltype(test<no_helloworld_class>(nullptr))::value << endl;
}