Christian Gollwitzer wrote:
You don't need to explain a vtable to explain dynamic_cast. Only if
you want to become a compiler writer. It is not even required, vtables
are just the most common implementation.
dynamic_cast simply checks if the actual object that the pointer
points to is an instance of a derived class, and then casts it into
that. You could "explain" it with the following pseudo-code
template <T*, base*>
T* dynamic_cast<T*>(base *input) {
if (isinstanceof(base, *input)) { return (T*)input; }
else { return nullptr; }
}
How that works (particularly the "isinstanceof") is not the business
of the programmer - it is sufficient to know that the compiler
somewhere stores this information for every object.
Christian
With that, the students would "boo you off the stage!"... and maybe
accuse you of being a "know it all". ; ) The point of college is
more about teaching students to think rather than in being efficient. I
have little doubt that a tech school could "get through everything" much
faster.
Bill
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