std::iter_swap
Defined in header <algorithm> | ||
|---|---|---|
template< class ForwardIt1, class ForwardIt2 > void iter_swap( ForwardIt1 a, ForwardIt2 b ); | (until C++20) | |
template< class ForwardIt1, class ForwardIt2 > constexpr void iter_swap( ForwardIt1 a, ForwardIt2 b ); | (since C++20) |
Swaps the values of the elements the given iterators are pointing to.
Parameters
| a, b | - | iterators to the elements to swap |
| Type requirements | ||
-ForwardIt1, ForwardIt2 must meet the requirements of LegacyForwardIterator. |
||
-*a, *b must meet the requirements of Swappable. |
||
Return value
(none).
Complexity
constant.
Possible implementation
template<class ForwardIt1, class ForwardIt2>
constexpr void iter_swap(ForwardIt1 a, ForwardIt2 b) // constexpr since C++20
{
using std::swap;
swap(*a, *b);
} |
Example
The following is an implementation of selection sort in C++
#include <random>
#include <vector>
#include <iostream>
#include <algorithm>
#include <functional>
template<class ForwardIt>
void selection_sort(ForwardIt begin, ForwardIt end)
{
for (ForwardIt i = begin; i != end; ++i)
std::iter_swap(i, std::min_element(i, end));
}
int main()
{
std::random_device rd;
std::mt19937 gen(rd());
std::uniform_int_distribution<> dist(-10, 10);
std::vector<int> v;
generate_n(back_inserter(v), 20, bind(dist, gen));
std::cout << "Before sort: ";
for(auto e : v) std::cout << e << " ";
selection_sort(v.begin(), v.end());
std::cout << "\nAfter sort: ";
for(auto e : v) std::cout << e << " ";
std::cout << '\n';
}Output:
Before sort: -7 6 2 4 -1 6 -9 -1 2 -5 10 -9 -5 -3 -5 -3 6 6 1 8 After sort: -9 -9 -7 -5 -5 -5 -3 -3 -1 -1 1 2 2 4 6 6 6 6 8 10
See also
| swaps the values of two objects (function template) |
|
| swaps two ranges of elements (function template) |
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