How to use a member variable as a default argument in C++?

Question

I want to make an argument for one of the member functions optional. When no argument is provided, it would use an member variable.

However, when I tried to compil

Answer 1

Besides overloading, another approach is passing an invalid value as the default value. Then check it inside your function.

void Object::MoveTo(double speed, Point position = InvalidPosition) {
   position = (position != InvalidPosition) ? position : initPos;
   ...
}