[sebstefan]

It doesn't have to be slow. There's a reason "Clean code" is being criticized everytime it's mentioned. It touts inheritance and polymorphism as a solution to everything like it's 2002. There's been enough "Inheritance considered harmful" articles to toss that aside

The take on switch statements is covered in "The Pragmatic programmer" as well, which coincidentally is much less criticized when it comes to books about clean code.

The way to fix the switch is getting rid of the class "shape" and making it an interface, then implementing the interface in each shape, as a non-virtual method. And then you don't let people inherit. They can compose instead.

Performance is unaffected, you get rid of the switch, the compiler catches your mistakes for you, and everyone's happy