savant

#include <iostream>

class AA {
        public:
        virtual int foo() = 0;
};

template<int p> class A : public AA {};

template<> class A<1> :public AA {
        public:
        int foo() {
                return 1;
        }
};

template<> class A<2> : public AA {
        public:
        int foo() {
                return 2;
        }
};

int main(int argc, char** argv){
        A<1> a1;
        A<2> a2;
        AA* a3 = &a2;
        std::cout << a1.foo() << std::endl << a2.foo() << std::endl << a3->foo() << std::endl;
        return 0;
}