any idea why I can't overload << as member function i.e Code: template<typename T> class Simple{ T A,B; public: /* Constructors and destructors */ T getA(){return A;} T getB(){return B;} ostream& operator(ostream& os){ return os<<A<<"-"<<B; } // this doesn't work } template<typename T> ostream& operator(ostream& os, Simple<T> P ) { return os<<P.getA()<<"-"<<p.getB(); } //this works I can overload the +, - inside and outside the class. But << and most probably >> has to be implemented as esternal function , why so ? any idea
sorry for the typo . it should read in both operator lines: "ostream& operator<<(ostream& os, Simple<T> P )"
Because they are not the internal members of the class. the format in which you specify is such that the function needs to be external. cout<<YourVariable<<endl; Now if you get into the operator overloading this should be OutputClassFunction.Operator <<(YourVariable) And so you need the first parameter as IO class variable and so you cannot have the function as internal.
