>>57
こうかな？ウザイな。

template<class T>
class MyClass;

template <class T>
std::ostream& operator<<(std::ostream& os, const MyClass<T>& m);

template <class T>
class MyClass {
...
friend std::ostream& operator<< <T> (std::ostream&, const MyClass&);
};

template <class T>
std::ostream& operator<<(std::ostream& os, const MyClass<T>& m) { ... }