"For each class with virtual functions, a vtable is created. Then, when an object of a class with a viable is created using a constructor, the constructor copies the appropriate vtable into the object. So each object has a pointer to its vtable ( or in the case of multiple inheritance, when necessary, a Orr to each of its vtables. ). The compiler knows where in the object the vtable is, so when it needs to call a virtual method, it outputs byte code to deterrence the vtable, lookup the appropriate method, and jump to its address".