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  1. #include <string>
  2. #include <tuple>
  3. #include <iostream>
  4.  
  5. template<typename Tuple, std::size_t... Is>
  6. void print_tuple(const Tuple& tup, std::index_sequence<Is...>);
  7.  
  8. template<typename Tuple>
  9. using tuple_indices = std::make_index_sequence<std::tuple_size<Tuple>::value>;
  10.  
  11. template<typename... Ts>
  12. class B {
  13. public:
  14.     B(int i, bool b, float f, const Ts&... rest) :
  15.             properties(std::make_tuple(i, b, f, rest...)) {
  16.     }
  17.     virtual std::string id() const = 0;
  18.     std::tuple<int, bool, float, Ts...> properties;
  19. };
  20.  
  21. class A : public B<float, std::string, std::string> {
  22.     using B::B;
  23.     virtual std::string id() const {
  24.     	return "Class A";
  25.     }
  26. };
  27.  
  28. class C : public B<std::string> {
  29.     using B::B;
  30.     virtual std::string id() const {
  31.     	return "Class C";
  32.     }
  33. };
  34.  
  35. template<typename... Ts>
  36. void test(const B<Ts...>& base) {
  37. 	std::cout << base.id() << '(';
  38.     print_tuple(base.properties, tuple_indices<decltype(base.properties)>{});
  39.     std::cout << ')' << std::endl;
  40. }
  41.  
  42. int main() {
  43.     A foo(12, true, 3.14, 6.28, "foo", "bar");
  44.     C baz(36, false, .33, "baz");
  45.  
  46.     test(foo);
  47.     test(baz);
  48. }
  49.  
  50. template<typename Tuple, std::size_t... Is>
  51. void print_tuple(const Tuple& tup, std::index_sequence<Is...>) {
  52.     using dummy = int[];
  53.     static_cast<void>(dummy {
  54.         0, (static_cast<void>(std::cout << (Is ? ", " : "") << std::get<Is>(tup)), 0)...
  55.     });
  56. }
Success #stdin #stdout 0s 16064KB
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stdin
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Standard input is empty
stdout
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Class A(12, 1, 3.14, 6.28, foo, bar)
Class C(36, 0, 0.33, baz)
https://ideone.com/Syr7LJ
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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