std::tuple_cat (3) - Linux Manuals

std::tuple_cat: std::tuple_cat

NAME

std::tuple_cat - std::tuple_cat

Synopsis

Defined in header <tuple>
template< class... Tuples > (since C++11)
std::tuple<CTypes...> tuple_cat(Tuples&&... args); (constexpr since C++14)

Constructs a tuple that is a concatenation of all tuples in args.

Parameters

args - zero or more tuples to concatenate

Return value

A std::tuple object composed of all elements of all argument tuples constructed from std::get<i>(std::forward<Ti>(arg)) for each individual element.

Example

// Run this code

  #include <iostream>
  #include <tuple>
  #include <string>

  // helper function to print a tuple of any size
  template<class Tuple, std::size_t N>
  struct TuplePrinter {
      static void print(const Tuple& t)
      {
          TuplePrinter<Tuple, N-1>::print(t);
          std::cout << ", " << std::get<N-1>(t);
      }
  };

  template<class Tuple>
  struct TuplePrinter<Tuple, 1> {
      static void print(const Tuple& t)
      {
          std::cout << std::get<0>(t);
      }
  };

  template<class... Args>
  void print(const std::tuple<Args...>& t)
  {
      std::cout << "(";
      TuplePrinter<decltype(t), sizeof...(Args)>::print(t);
      std::cout << ")\n";
  }
  // end helper function

  int main()
  {
      std::tuple<int, std::string, float> t1(10, "Test", 3.14);
      int n = 7;
      auto t2 = std::tuple_cat(t1, std::make_pair("Foo", "bar"), t1, std::tie(n));
      n = 10;
      print(t2);
  }

Output:

  (10, Test, 3.14, Foo, bar, 10, Test, 3.14, 10)