You can also perform conversions. In math, you can define a vector that represents direction, so that the line drawn between two points is a vector. In our code we have already defined a point class and a cartesian_vector class. You could decide to have a constructor that creates a vector between the origin and a point, in which case you are converting a point object to a cartesian_vector object:

    class cartesian_vector 
    { 
        double x; double y;  
    public: 
        cartesian_vector(const point& p) : x(p.x), y(p.y) {} 
    };

There is a problem here, which we will address in a moment. The conversions can be called like this:

    point p(10, 10); 
    cartesian_vector v1(p); 
    cartesian_vector v2 { p }; 
    cartesian_vector v3 = p;