text: template <class U>
  class Adder {
      public:
          U arg0, arg1;
          Adder(): arg0(0), arg1(0) { };
          Adder(U i0, U i1): arg0(i0), arg1(i1) { };
          Adder(const Adder & o) : arg0(o.arg0), arg1(o.arg1) { };
          U getSum() {
              return arg0+ arg1;
          }
  };
  