#include <iostream>

template <class R>
class Convert;

template <class R, class T>
class Convert<R (T)>
{
public:
	R operator()(T arg)
	{
		return static_cast<R>(arg);
	}
};

int main()
{
	Convert<int(float)> floor;
	std::cout << floor(3.14159) << std::endl;
	return 0;
}

3