std::tuple::swap (非メンバ関数)(C++11)

namespace std {
  template <class... Types>
  void swap(tuple<Types...>& x, tuple<Types...>& y)
    noexcept(noexcept(x.swap(y)));
}

x.swap(y);

#include <string>
#include <tuple>
#include <cassert>

int main()
{
  std::tuple<int, char, std::string> a(1, 'a', "hello");
  std::tuple<int, char, std::string> b(2, 'b', "good-bye");

  std::swap(a, b);

  assert(a == std::make_tuple(2, 'b', "good-bye"));
  assert(b == std::make_tuple(1, 'a', "hello"));
}