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  1. #include <iostream>
  2. #include <vector>
  3. #include <tuple>
  4. #include <utility>
  5.  
  6.     class ColumnBase {
  7.       std::string m_name;
  8.     public:
  9.       ColumnBase(const std::string& name) : m_name(name) {}
  10.       std::string name() { return m_name; }
  11.     };
  12.  
  13.     template<class T>
  14.     class Column : public ColumnBase {
  15.       std::vector<T> m_items;
  16.      public:
  17.       Column(const std::string& name) :ColumnBase(name) {}
  18.     };
  19.  
  20.     template<class... T>
  21.     class Table {
  22.       std::tuple<Column<T>...> m_columns;
  23.  
  24.       template<std::size_t... index>
  25.       std::vector<ColumnBase*> columns_vec_helper(std::index_sequence<index...>) {
  26.         return { (&std::get<index>(m_columns))... };
  27.       }
  28.  
  29.     public:
  30.       Table(Column<T>&&... columns) : m_columns(std::move(columns)...) {}
  31.  
  32.       std::vector<ColumnBase*> columns_vec() {
  33.         return columns_vec_helper(std::make_index_sequence<sizeof...(T)>{});
  34.       }
  35.     };
  36.  
  37.  
  38. int main() {
  39. 	Table<std::size_t, std::string, int, int> t ({"id"}, {"name"}, {"x"}, {"y"});
  40. 	for (const auto& colBase : t.columns_vec()) std::cout << "column " << colBase->name() << "\n";
  41. 	return 0;
  42. }
Success #stdin #stdout 0s 3464KB
comments (?)
stdin 
Standard input is empty
stdout 
column id
column name
column x
column y
https://ideone.com/tTD6sQ
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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