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std::swap_ranges

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< cpp‎ | algorithm
 
 
Algorithm library
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Modifying sequence operations
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C library
 
Defined in header <algorithm>
template<class ForwardIt1, class ForwardIt2 >
ForwardIt2 swap_ranges( ForwardIt1 first1, ForwardIt1 last1, ForwardIt2 first2 );
(1)
template<class ExecutionPolicy, class ForwardIt1, class ForwardIt2 >
ForwardIt2 swap_ranges( ExecutionPolicy&& policy, ForwardIt1 first1, ForwardIt1 last1, ForwardIt2 first2 );
(2) (since C++17)
1) Exchanges elements between range [first1, last1) and another range starting at first2.
2) Same as (1), but executed according to policy. This overload does not participate in overload resolution unless std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true

Contents

[edit]Parameters

first1, last1 - the first range of elements to swap
first2 - beginning of the second range of elements to swap
policy - the execution policy to use. See execution policy for details.
Type requirements
-
ForwardIt1, ForwardIt2 must meet the requirements of ForwardIterator.
-
The types of dereferenced ForwardIt1 and ForwardIt2 must meet the requirements of Swappable

[edit]Return value

Iterator to the element past the last element exchanged in the range beginning with first2.

[edit]Exceptions

The overload with a template parameter named ExecutionPolicy reports errors as follows:

  • If execution of a function invoked as part of the algorithm throws an exception and ExecutionPolicy is one of the three standard policies, std::terminate is called. For any other ExecutionPolicy, the behavior is implementation-defined.
  • If the algorithm fails to allocate memory, std::bad_alloc is thrown.

[edit]Possible implementation

template<class ForwardIt1, class ForwardIt2> ForwardIt2 swap_ranges(ForwardIt1 first1, ForwardIt1 last1, ForwardIt2 first2){while(first1 != last1){std::iter_swap(first1++, first2++);}return first2;}

[edit]Example

Demonstrates swapping of subranges from different containers

#include <algorithm>#include <list>#include <vector>#include <iostream>int main(){std::vector<int> v ={1, 2, 3, 4, 5};std::list<int> l ={-1, -2, -3, -4, -5};   std::swap_ranges(v.begin(), v.begin()+3, l.begin());   for(int n : v)std::cout<< n <<' ';std::cout<<'\n';for(int n : l)std::cout<< n <<' ';std::cout<<'\n';}

Output:

-1 -2 -3 4 5 1 2 3 -4 -5

[edit]Complexity

linear in the distance between first1 and last1

[edit]See also

swaps the elements pointed to by two iterators
(function template)[edit]
swaps the values of two objects
(function template)[edit]
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