As some answers already pointed out, set/get don't have to actually set or return actual members.
For example, let's say you have a Coordinate class with set/get for (x, y). The inner implementation might be based on polar coordinates:
private double radius;private double angle;and the get/set for (x, y) do some coordinate transformation with sin and cos.
You could change the implementation of the class to any other system of coordinate at will and still just keep the set/get for (x, y) as public methods.
So, to sum up, my answer to the question would be: the public interface of a class might provide set/get, but the actual implementation can (and should) be hidden by making all members private (or protected). So we could say that having public set/get on private data is "implementation hiding" rather than data hiding.
