#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;
}

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