I agree, but that's the thing: It is non idomatic to write immutable Shape-style classes in C++. Possible, yes. Idiomatic, no. IIRC in Stroustroup's book (the

I agree, but that's the thing: It is non idomatic to write immutable Shape-style classes in C++. Possible, yes. Idiomatic, no. IIRC in Stroustroup's book (the one I read a decade ago, anyway), he concludes that Rect:Square and Circle:Ellipse can not inherit from each other in either direction, and did not suggest switching to immutable everything.