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

There is nothing special about double-overloading than other primitive types overloadings. In this case, it is the only primitive overload available. The compiler will behave the same for int, char, etc..

Notice that if we would have more than one primitive type overload the compiler will throw

error: ambiguous overload for 'operator<<' ...