What is reverse assignment? Why does it require a run-time check? What is a vtable? How is it used? What is the fragile base class problem? What is an abstract (deferred) class? Explain the importance...

What is reverse assignment? Why does it require a run-time check? What is a vtable? How is it used? What is the fragile base class problem? What is an abstract (deferred) class? Explain the importance of virtual methods for object closures. What is mix-in inheritance? What problem does it solve?