What is the best way to indicate that a double value has not been initialized?

Question

I have a class CS which is to represent the co-ordinate system in 3D i.e.(x, y, z)

class CS
{
  private:
        double x;
        double y;
        double z         


        

Answer 1

You can't change the address of a variable. And you can't assign pointer values (like NULL, or nullptr in C++) to a variable of a non-pointer type, such as double.