NAME¶

std::iter_swap(std::reverse_iterator) - std::iter_swap(std::reverse_iterator)

Synopsis¶

template< std::indirectly_swappable<Iter> Iter2 >

friend constexpr void
iter_swap( const reverse_iterator& x, (since C++20)

const std::reverse_iterator<Iter2>& y )
noexcept(/*see below*/);

Swaps the objects pointed to by two adjusted underlying iterators. The function body
is equivalent to:

auto tmp_x = x.base();
auto tmp_y = y.base();
ranges::iter_swap(--tmp_x, --tmp_y);

This function template is not visible to ordinary unqualified or qualified lookup,
and can only be found by argument-dependent lookup when std::reverse_iterator<Iter>
is an associated class of the arguments.

Parameters¶

x, y - reverse iterators to the elements to swap

Return value¶

(none)

Complexity¶

Constant.

Exceptions¶

noexcept specification:
noexcept(

std::is_nothrow_copy_constructible_v<Iter> &&
std::is_nothrow_copy_constructible_v<Iter2> &&
noexcept(ranges::iter_swap(--std::declval<Iter&>(), --std::declval<Iter2&>()))

)

Example¶

// Run this code

#include <iostream>
#include <iterator>
#include <list>
#include <vector>

int main()
{
std::vector v{1, 2, 3};
std::list l{4, 5, 6};

std::reverse_iterator<std::vector<int>::iterator> r1{v.rbegin()};
std::reverse_iterator<std::list<int>::iterator> r2{l.rbegin()};

std::cout << *r1 << ' ' << *r2 << '\n';

iter_swap(r1, r2); // ADL

std::cout << *r1 << ' ' << *r2 << '\n';
}

Output:¶

3 6
6 3

See also¶

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

Category:¶

* conditionally noexcept