Write the definition of area out of the class in C++

Question

In the following code, how could we write the definiton of area out of the class ?

class Rectangle {
        public:
        double hauteur;
        double largeur;
        double area() {
            return hauteur*largeur;
        }
    };

Accepted Answer

By letting the prototype of area in the class and putting out its definiton with the prefix *Rectangle::*.

Answer

You can not put out of a class a method definition.

Answer

By writting the protoype and the definiton out of the class.

Answer

By putting out the prototype with the prefix *Rectangle::* and letting in the class its definiton.

Question from the C++ - Fundamentals test

Write the definition of area out of the class in C++