class has no member "operator<<"
c++, insertion, ostream
Solution
It's not a member of the `Animal` class, nor should it be. So don't define it as one. Define it as a free function by removing the `Animal::` prefix.
ostream & operator<< (ostream & o, Dog & d){
//...
}
Problem
I have read through Should operator<< be implemented as a friend or as a member function? and Overloading Insertion Operator in C++, looks like the similar problem, but didn't fix my own problem. My header file: ``` using namespace std; class Animal { private: friend ostream & operator<< (ostream & o, Dog & d); int number; public: Animal(int i); int getnumber(); }; ostream & operator<< (ostream & o, Dog & d); ``` My cpp: ``` using namespace std; int Animal::getnumber(){ return number; } ostream & Animal::operator<< (ostream & o, Dog & d){ //... } Animal::Animal(int i) : number(i){} ``` Implementation is simple, but I am getting the error: in cpp - Error: class "Animal" class has no member "operator<<". I don't really get it because I already declared insertion operator as a friend in Animal, why am I still getting this error? (put the ostream in public doesn't help)