#include <iostream>
template<class T> class DeviceType;

//replaced DeviceType with class in template parameters
template <class T> std::ostream& operator<< (std::ostream& output, const DeviceType<T>& dev);

template <class T> class DeviceType {
     friend std::ostream & operator<< <>(std::ostream & output, const DeviceType<T> & deviceType );
};

int main(){}