I am using the NPointD data type.
But the Rotate and Translate functions I need are not working.
I haven't tested other functions in the class, but I think it won't work.

Check the function operation of the class.

The example code is shown below.

NPoint p1 = new NPointD (10.0,10.0);

// p1 X, Y does not change
p1.Rotate(30.0);

// p1 X, Y does not change
p1.Translate (3.0,3.0);

please answer about my question.