extern bool operator> (Time const & a, Time const & b);
extern bool operator>= (Time const & a, Time const & b);
extern std::ostream & operator<< (std::ostream & s, Time const & t);
-extern Time operator+ (Time a, Time b);
+extern Time operator+ (Time a, Time b);
extern Time operator- (Time a, Time b);
extern float operator/ (Time a, Time const & b);