Unclear use of operator double()

Question

I have a Rectangle class with conversion operators to both double and std::string:

class Rectangle
{
public:
    Rectangle         


        

Answer 1

You do not have an operator to output the rectangle to the stream. cout does have an overload that takes a double and your class can be implicitly converted to a double so that is chosen.

The reason the string overload is not selected and is not considered as an ambiguity is because operator << for a string is a member function and is not included in the member overload and non member overload set of cout. If we comment out the operator double we can see we get a compiler error.

If we want to have the operator string called then we would need to explicitly cast r into a string. Live Example