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std::tuple_cat(3)	      C++ Standard Libary	     std::tuple_cat(3)

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.

	  The  behavior	is undefined if	any type in std::decay_t<Tuples>... is
       not a
	  specialization of std::tuple.	However, an implementation may	choose
       to support types
	  (such	as std::array and std::pair) that follow the tuple-like	proto-
       col.

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<j>(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<typename... Args, std::enable_if_t<sizeof...(Args) == 0, int>
       = 0>
	void print(const std::tuple<Args...>& t)
	{
	    std::cout << "()\n";
	}

	template<typename... Args, std::enable_if_t<sizeof...(Args) != 0, int>
       = 0>
	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_tuple("Foo",  "bar"),  t1,
       std::tie(n));
	    n =	42;
	    print(t2);
	}

Output:
	(10, Test, 3.14, Foo, bar, 10, Test, 3.14, 42)

See also
	  make_tuple	    creates  a tuple object of the type	defined	by the
       argument	types
	  (C++11)	   (function template)
	  tie		   creates a tuple of lvalue references	or  unpacks  a
       tuple into
	  (C++11)	   individual objects
			   (function template)
	  forward_as_tuple creates a tuple of forwarding references
	  (C++11)	   (function template)

http://cppreference.com		  2022.07.31		     std::tuple_cat(3)

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