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