May I use a constant number to choose a class at compile time, possibly using templates?

Question

Let\'s say I have a constant value (possibly of some enum type). Let\'s say I have many classes A, B, D, etc.

Can I have something like this?

C<1>          


        

Answer 1

Using the LSP and plain C++98:

template  class C;
template <> class C<1> : public A {};
template <> class C<2> : public B {};
template <> class C<3> : public D {};

C<1> anInstanceOfA;

Since public inheritance in C++ satisfies the IS-A rule, anInstanceOfA both IS-A C<1> object and IS_AN A object.