Item 46: Define non-member functions inside templates when type conversions are desired

Item 24 explains why only non-member functions are eligible for implicit type conversions on all arguments, and it uses as an example the operator* function for a Rational class. I recommend you familiarize yourself with that example before continuing, because this Item extends the discussion with a seemingly innocuous modification to Item 24's example: it templatizes both Rational and operator*: