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std::ranges::in_in_result(3)  C++ Standard Libary std::ranges::in_in_result(3)

NAME
       std::ranges::in_in_result - std::ranges::in_in_result

Synopsis
	  Defined in header <algorithm>
	  template< class I1, class I2 >  (since C++20)
	  struct in_in_result;

	  ranges::in_in_result	is  a  class  template	that provides a	way to
       store two iterators
	  as a single unit.

	  This class template has no base classes or  declared	members	 other
       than those shown
	  below. Thus it is suitable for use with structured bindings.

	  All  special	member functions of this class template	are implicitly
       declared, which
	  makes	specializations	be aggregate classes, and  propagate  trivial-
       ity,
	  potentially-throwing-ness, and constexpr-ness	of corresponding oper-
       ations on data
	  members.

Template parameters
	  I1,  I2  -  the types	of the iterators that the ranges::in_in_result
       stores.

	  Data members

	  Member name Definition
	  in1	      a	value (that is supposed	to be an iterator) of type I1.
		      (public member object)
	  in2	      a	value (that is supposed	to be an iterator) of type I2.
		      (public member object)

	  All these members are	declared with [[no_unique_address]] attribute.

Member functions
       std::ranges::in_in_result::operator in_in_result<II1, II2>

	  template<class II1, class II2>

	  requires  std::convertible_to<const  I1&,  II1>   &&	 std::convert-
       ible_to<const I2&,  (1)
	  II2>

	  constexpr operator in_in_result<II1, II2>() const &;
	  template<class II1, class II2>

	  requires  std::convertible_to<I1,  II1>  &&  std::convertible_to<I2,
       II2>	      (2)

	  constexpr operator in_in_result<II1, II2>() &&;

	  Converts *this to the	result by constructing every  data  member  of
       the result from
	  the corresponding member of *this.

	  1) Equivalent	to return {in1,	in2};.
	  2) Equivalent	to return {std::move(in1), std::move(in2)};.

Standard library
	  The following	standard library functions use ranges::in_in_result as
       the return
	  type:

		Algorithm functions
	  ranges::mismatch    finds the	first position where two ranges	differ
	  (C++20)	      (niebloid)
	  ranges::swap_ranges swaps two	ranges of elements
	  (C++20)	      (niebloid)

Synopsis
	namespace std::ranges
	{
	    template<class I1, class I2>
	    struct in_in_result
	    {
		[[no_unique_address]] I1 in1;
		[[no_unique_address]] I2 in2;

		template<class II1, class II2>
		requires  std::convertible_to<const I1&, II1> && std::convert-
       ible_to<const I2&, II2>
		constexpr operator in_in_result<II1, II2>() const &
		{
		    return {in1, in2};
		}

		template<class II1, class II2>
		requires   std::convertible_to<I1,   II1>   &&	 std::convert-
       ible_to<I2, II2>
		constexpr operator in_in_result<II1, II2>() &&
		{
		    return {std::move(in1), std::move(in2)};
		}
	    };
	}

Notes
	  Each	standard  library  algorithm  that  uses this family of	return
       types declares a	new
	  alias	type, e.g. using merge_result =	in_in_out_result<I1, I2, O>;.

	  The names for	such aliases are formed	by adding the suffix "_result"
       to the
	  algorithm's name. So,	the return type	of std::ranges::merge  can  be
       named as
	  std::ranges::merge_result.

	  Unlike  std::pair  and std::tuple, this class	template has data mem-
       bers of meaningful
	  names.

Example
       // Run this code

	#include <algorithm>
	#include <iostream>
	#include <ranges>

	int main()
	{
	    constexpr static auto in1 =	{1, 2, 3, 4};
	    constexpr static auto in2 =	{1, 2, 4, 5};

	    constexpr auto result {std::ranges::mismatch(in1, in2)};

	    static_assert(2    ==    std::ranges::distance(in1.begin(),	   re-
       sult.in1));
	    static_assert(2    ==    std::ranges::distance(in2.begin(),	   re-
       sult.in2));
	}

See also
	  pair	  implements binary tuple, i.e.	a pair of values
		  (class template)
	  tuple	  implements fixed size	container,  which  holds  elements  of
       possibly	different
	  (C++11) types
		  (class template)

http://cppreference.com		  2024.06.10	  std::ranges::in_in_result(3)

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