std::ranges::swap_ranges, std::ranges::swap_ranges_result

 

C++

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Freestanding and hosted

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Standard library headers

Named requirements

Feature test macros(C++20)

Language support library

Concepts library(C++20)

Diagnostics library

Memory management library

Metaprogramming library(C++11)

General utilities library

Containers library

Iterators library

Ranges library(C++20)

Algorithms library

Strings library

Text processing library

Numerics library

Date and time library

Input/output library

Filesystem library(C++17)

Concurrency support library(C++11)

Execution control library(C++26)

Technical specifications

Symbols index

External libraries

 

Algorithm library

Constrained algorithms and algorithms on ranges(C++20)
Constrained algorithms, e.g. ranges::copy, ranges::sort, ...
Execution policies (C++17)
is_execution_policy (C++17)   execution::seqexecution::parexecution::par_unseqexecution::unseq (C++17)    (C++17)(C++17)(C++20)	execution::sequenced_policyexecution::parallel_policyexecution::parallel_unsequenced_policyexecution::parallel_unsequenced (C++17)(C++17)(C++17)(C++20)
Non-modifying sequence operations Batch operations for_each for_each_n (C++17) Search operations all_ofany_ofnone_of (C++11)                (C++11)(C++11) countcount_if mismatch equal findfind_iffind_if_not (C++11) find_end find_first_of adjacent_find search search_n Modifying sequence operations Copy operations copycopy_if (C++11) copy_backward copy_n (C++11) move (C++11) move_backward (C++11) Swap operations swap iter_swap swap_ranges Transformation operations replacereplace_if transform replace_copyreplace_copy_if Generation operations fill fill_n generate generate_n Removing operations removeremove_if unique remove_copyremove_copy_if unique_copy Order-changing operations reverse reverse_copy rotate rotate_copy random_shuffleshuffle (until C++17)(C++11) shift_leftshift_right (C++20)(C++20) Sampling operations sample (C++17)	Sorting and related operations Partitioning operations partition partition_copy (C++11)   stable_partition is_partitioned (C++11) partition_point (C++11) Sorting operations sort stable_sort partial_sort partial_sort_copy is_sorted (C++11) is_sorted_until (C++11) nth_element Binary search operations (on partitioned ranges) lower_bound upper_bound equal_range binary_search Set operations (on sorted ranges) includes set_union set_intersection set_difference set_symmetric_difference Merge operations (on sorted ranges) merge inplace_merge Heap operations push_heap pop_heap make_heap sort_heap is_heap (C++11) is_heap_until (C++11) Minimum/maximum operations max min minmax (C++11) clamp (C++17) max_element min_element minmax_element (C++11) Lexicographical comparison operations lexicographical_compare lexicographical_compare_three_way (C++20) Permutation operations next_permutation prev_permutation is_permutation (C++11) C library qsort bsearch
Numeric operations
iota (C++11) inner_product adjacent_difference    accumulate reduce (C++17) transform_reduce (C++17)	partial_sum inclusive_scan (C++17)    exclusive_scan (C++17) transform_inclusive_scan (C++17) transform_exclusive_scan (C++17)
Operations on uninitialized memory
uninitialized_copy uninitialized_move (C++17)    uninitialized_fill uninitialized_copy_n (C++11) uninitialized_move_n (C++17) uninitialized_fill_n	destroy (C++17) destroy_n (C++17) destroy_at (C++17) construct_at (C++20)       uninitialized_default_construct (C++17) uninitialized_value_construct (C++17) uninitialized_default_construct_n (C++17) uninitialized_value_construct_n (C++17)

 

Constrained algorithms

All names in this menu belong to namespace std::ranges

Non-modifying sequence operations

all_ofany_ofnone_of for_each for_each_n    countcount_if adjacent_find mismatch equal lexicographical_compare    containscontains_subrange (C++23)(C++23) findfind_iffind_if_not find_lastfind_last_iffind_last_if_not (C++23)(C++23)(C++23)   find_end find_first_of search search_n starts_with (C++23) ends_with (C++23)

Modifying sequence operations

copycopy_if copy_n copy_backward    move move_backward shift_leftshift_right (C++23)(C++23)   fill fill_n generate generate_n    transform swap_ranges    shuffle sample removeremove_if replacereplace_if reverse rotate remove_copyremove_copy_if    unique replace_copyreplace_copy_if reverse_copy rotate_copy unique_copy

Partitioning operations

is_partitioned    partition_point    partition    partition_copy    stable_partition

Sorting operations

is_sorted is_sorted_until     sort stable_sort         partial_sort       nth_element partial_sort_copy

Binary search operations (on sorted ranges)

lower_bound         upper_bound         binary_search      equal_range

Set operations (on sorted ranges)

merge inplace_merge       set_difference set_intersection    set_union          includes set_symmetric_difference

Heap operations

is_heap is_heap_until       make_heap           sort_heap push_heap pop_heap

Minimum/maximum operations

max max_element         min min_element         minmax minmax_element     clamp

Permutation operations

is_permutation      next_permutation    prev_permutation

Fold operations

fold_left (C++23) fold_left_first (C++23)   fold_right (C++23) fold_right_last (C++23)   fold_left_with_iter (C++23) fold_left_first_with_iter (C++23)

Numeric operations iota (C++23)             Random number generation generate_random (C++26)

Operations on uninitialized storage

construct_at    destroy destroy_n destroy_at uninitialized_copy    uninitialized_move uninitialized_fill uninitialized_copy_n    uninitialized_move_n uninitialized_fill_n uninitialized_default_construct uninitialized_default_construct_n uninitialized_value_construct uninitialized_value_construct_n

Return types

in_fun_result in_in_result in_found_result    in_out_result in_in_out_result    in_out_out_result    min_max_result out_value_result (C++23) in_value_result (C++23)

 

Defined in header <algorithm>
Call signature
template<std::input_iterator I1, std::sentinel_for<I1> S1,           std::input_iterator I2, std::sentinel_for<I2> S2 > requires std::indirectly_swappable<I1, I2> constexpr swap_ranges_result<I1, I2>     swap_ranges( I1 first1, S1 last1, I2 first2, S2 last2 );	(1)	(since C++20)
template<ranges::input_range R1, ranges::input_range R2 > requires std::indirectly_swappable<ranges::iterator_t<R1>, ranges::iterator_t<R2>> constexpr swap_ranges_result<ranges::borrowed_iterator_t<R1>,                              ranges::borrowed_iterator_t<R2>>     swap_ranges( R1&& r1, R2&& r2 );	(2)	(since C++20)
Helper types
template<class I1, class I2 > using swap_ranges_result =ranges::in_in_result<I1, I2>;	(3)	(since C++20)

1) Exchanges elements between first range [first1, first1 + M) and second range [first2, first2 + M) via ranges::iter_swap(first1 + i, first2 + i), where M =ranges::min(ranges::distance(first1, last1), ranges::distance(first2, last2)).

The ranges [first1, last1) and [first2, last2) must not overlap.

2) Same as (1), but uses r1 as the first range and r2 as the second range, as if using ranges::begin(r1) as first1, ranges::end(r1) as last1, ranges::begin(r2) as first2, and ranges::end(r2) as last2.

The function-like entities described on this page are algorithm function objects (informally known as niebloids), that is:

• Explicit template argument lists cannot be specified when calling any of them.
• None of them are visible to argument-dependent lookup.
• When any of them are found by normal unqualified lookup as the name to the left of the function-call operator, argument-dependent lookup is inhibited.

Parameters

first1, last1	-	the iterator-sentinel pair defining the first range of elements to swap
first2, last2	-	the iterator-sentinel pair defining the second range of elements to swap
r1	-	the first range of elements to swap
r2	-	the second range of elements to swap.

Return value

{first1 + M, first2 + M}.

Complexity

Exactly M swaps.

Notes

Implementations (e.g. MSVC STL) may enable vectorization when the iterator type models contiguous_iterator and swapping its value type calls neither non-trivial special member function nor ADL-found swap.

Possible implementation

struct swap_ranges_fn {template<std::input_iterator I1, std::sentinel_for<I1> S1, std::input_iterator I2, std::sentinel_for<I2> S2> requires std::indirectly_swappable<I1, I2>constexpr ranges::swap_ranges_result<I1, I2> operator()(I1 first1, S1 last1, I2 first2, S2 last2)const{for(;!(first1 == last1 or first2 == last2);++first1, ++first2)ranges::iter_swap(first1, first2);return{std::move(first1), std::move(first2)};}   template<ranges::input_range R1, ranges::input_range R2> requires std::indirectly_swappable<ranges::iterator_t<R1>, ranges::iterator_t<R2>>constexpr ranges::swap_ranges_result<ranges::borrowed_iterator_t<R1>, ranges::borrowed_iterator_t<R2>> operator()(R1&& r1, R2&& r2)const{return(*this)(ranges::begin(r1), ranges::end(r1), ranges::begin(r2), ranges::end(r2));}};   inlineconstexpr swap_ranges_fn swap_ranges {};

Example

Run this code

#include <algorithm>#include <iostream>#include <list>#include <string_view>#include <vector>   auto print(std::string_view name, autoconst& seq, std::string_view term ="\n"){std::cout<< name <<" : ";for(constauto& elem : seq)std::cout<< elem <<' ';std::cout<< term;}   int main(){std::vector<char> p {'A', 'B', 'C', 'D', 'E'};std::list<char> q {'1', '2', '3', '4', '5', '6'};   print("p", p); print("q", q, "\n\n");   // swap p[0, 2) and q[1, 3): std::ranges::swap_ranges(p.begin(), p.begin()+4, std::ranges::next(q.begin(), 1), std::ranges::next(q.begin(), 3)); print("p", p); print("q", q, "\n\n");   // swap p[0, 5) and q[0, 5): std::ranges::swap_ranges(p, q);   print("p", p); print("q", q);}

Output:

p : A B C D E q : 1 2 3 4 5 6   p : 2 3 C D E q : 1 A B 4 5 6   p : 1 A B 4 5 q : 2 3 C D E 6

See also

iter_swap (C++20)	swaps the values referenced by two dereferenceable objects (customization point object)
ranges::swap (C++20)	swaps the values of two objects (customization point object)
swap_ranges	swaps two ranges of elements (function template)
iter_swap	swaps the elements pointed to by two iterators (function template)
swap	swaps the values of two objects (function template)