Difference between revisions of "cpp/iterator/reverse iterator/iter swap"
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< cpp | iterator | reverse iterator
Andreas Krug (Talk | contribs) m (fmt, .) |
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| − | {{cpp/title|iter_swap | + | {{cpp/title|iter_swap(std::reverse_iterator)}} |
{{cpp/iterator/reverse_iterator/navbar}} | {{cpp/iterator/reverse_iterator/navbar}} | ||
| − | {{ | + | {{|since=c++20| |
| − | + | ||
template< std::indirectly_swappable<Iter> Iter2 > | template< std::indirectly_swappable<Iter> Iter2 > | ||
| − | + | friend constexpr void iter_swap( const reverse_iterator& x, | |
| − | + | const std::reverse_iterator<Iter2>& y ) | |
| − | + | noexcept(/* see below */); | |
}} | }} | ||
| − | |||
| − | Swaps the objects pointed to by two adjusted underlying iterators. | + | Swaps the objects pointed to by two adjusted underlying iterators. |
| − | {{ | + | {{|auto tmp_x =x.base();auto tmp_y =y.base();ranges::iter_swap(--tmp_x, --tmp_y);}} |
| − | auto tmp_x = x.base(); | + | |
| − | auto tmp_y = y.base(); | + | |
| − | ranges::iter_swap(--tmp_x, --tmp_y); | + | |
| − | }} | + | |
| − | {{cpp/hidden friend|std::reverse_iterator<Iter>|tmpl=yes}} | + | {{cpp/hidden friend|std::reverse_iterator<Iter>|tmpl=yes}} |
===Parameters=== | ===Parameters=== | ||
| Line 24: | Line 18: | ||
{{par|x, y|reverse iterators to the elements to swap}} | {{par|x, y|reverse iterators to the elements to swap}} | ||
{{par end}} | {{par end}} | ||
| − | |||
| − | |||
| − | |||
===Complexity=== | ===Complexity=== | ||
| Line 50: | Line 41: | ||
std::vector v{1, 2, 3}; | std::vector v{1, 2, 3}; | ||
std::list l{4, 5, 6}; | std::list l{4, 5, 6}; | ||
| − | + | ||
std::reverse_iterator<std::vector<int>::iterator> r1{v.rbegin()}; | std::reverse_iterator<std::vector<int>::iterator> r1{v.rbegin()}; | ||
std::reverse_iterator<std::list<int>::iterator> r2{l.rbegin()}; | std::reverse_iterator<std::list<int>::iterator> r2{l.rbegin()}; | ||
| − | + | ||
std::cout << *r1 << ' ' << *r2 << '\n'; | std::cout << *r1 << ' ' << *r2 << '\n'; | ||
| − | + | ||
iter_swap(r1, r2); // ADL | iter_swap(r1, r2); // ADL | ||
| − | + | ||
std::cout << *r1 << ' ' << *r2 << '\n'; | std::cout << *r1 << ' ' << *r2 << '\n'; | ||
} | } | ||
Latest revision as of 23:29, 4 November 2024
| template< std::indirectly_swappable<Iter> Iter2 > friend constexpr void iter_swap( const reverse_iterator& x, |
(since C++20) | |
Swaps the objects pointed to by two adjusted underlying iterators.
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.
Contents |
[edit] Parameters
| x, y | - | reverse iterators to the elements to swap |
[edit] Complexity
Constant.
[edit] 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&>()))
[edit] 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
[edit] See also
| swaps the values of two objects (function template) | |
| swaps two ranges of elements (function template) | |
| swaps the elements pointed to by two iterators (function template) | |
| (C++20) |
swaps the values referenced by two dereferenceable objects (customization point object) |
| (C++20) |
swaps the objects pointed to by two underlying iterators (function template) |
