Defined in header <algorithm> | ||
---|---|---|
template< class I1, class I2 > struct in_in_result; | (since C++20) |
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 triviality, potentially-throwing-ness, and constexpr-ness of corresponding operations on data members.
I1, I2 | - | the types of the iterators that the ranges::in_in_result stores. |
[[no_unique_address]] I1 in1; |
a value (that is supposed to be an iterator).
[[no_unique_address]] I2 in2; |
a value (that is supposed to be an iterator).
template<class II1, class II2> requires std::convertible_to<const I1&, II1> && std::convertible_to<const I2&, II2> constexpr operator in_in_result<II1, II2>() const &; | (1) | |
template<class II1, class II2> requires std::convertible_to<I1, II1> && std::convertible_to<I2, II2> constexpr operator in_in_result<II1, II2>() &&; | (2) |
Converts *this
to the result by constructing every data member of the result from the corresponding member of *this
.
return {in1, in2};
.return {std::move(in1), std::move(in2)};
. The following standard library functions use ranges::in_in_result
as the return type:
Algorithm functions |
|
(C++20) | finds the first position where two ranges differ (niebloid) |
(C++20) | swaps two ranges of elements (niebloid) |
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::convertible_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::convertible_to<I2, II2> constexpr operator in_in_result<II1, II2>() && { return {std::move(in1), std::move(in2)}; } }; }
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 members of meaningful names.
#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(), result.in1)); static_assert(2 == std::ranges::distance(in2.begin(), result.in2)); }
implements binary tuple, i.e. a pair of values (class template) |
|
(C++11) | implements fixed size container, which holds elements of possibly different types (class template) |
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