1template<int N> struct val { char a[N]; }; 2 3class Base 4{ 5public: 6 virtual val<1> get1() const = 0; 7 virtual val<2> get2() const = 0; 8 virtual val<3> get3() const = 0; 9 virtual val<4> get4() const = 0; 10}; 11 12class Derived : public virtual Base 13{ 14public: 15 virtual val<1> get1() const { return foo->get1(); } 16 virtual val<2> get2() const { return foo->get2(); } 17 virtual val<3> get3() const { return foo->get3(); } 18 virtual val<4> get4() const { return foo->get4(); } 19 Base *foo; 20}; 21 22Base* make() { return new Derived; } 23