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iter_swap(std::counted_iterator)

From cppreference.com
 
 
Iterator library
Iterator concepts
Iterator primitives
Algorithm concepts and utilities
Indirect callable concepts
Common algorithm requirements
Utilities
(C++20)
Iterator adaptors
Stream iterators
Iterator customization points
Iterator operations
(C++11)
(C++11)
Range access
(C++11)(C++14)
(C++11)(C++14)
(C++17)(C++20)
(C++14)(C++14)
(C++14)(C++14)
(C++17)
(C++17)
 
 
template< std::indirectly_swappable<I> I2 >

  friend constexpr void
    iter_swap( const counted_iterator& x, const std::counted_iterator<I2>& y )

      noexcept(noexcept(ranges::iter_swap(x.base(), y.base())));
(since C++20)

Swaps the objects pointed to by two underlying iterators. The behavior is undefined if either x.count() or y.count() is equal to 0.

The function body is equivalent to: ranges::iter_swap(x.base(), y.base());.

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

Contents

[edit] Parameters

x, y - iterator adaptors to the elements to swap

[edit] Return value

(none)

[edit] Complexity

Constant.

[edit] Example

#include <iostream>
#include <iterator>
#include <list>
#include <vector>
 
int main()
{
    std::vector p { 1, 2, 3, 4 },
                q { 5, 6, 7, 8 };
 
    std::counted_iterator<std::vector<int>::iterator> ip { p.begin(), 2 };
    std::counted_iterator<std::vector<int>::iterator> iq { q.begin(), 3 };
 
    std::cout << *ip << ' ' << *iq << '\n';
    iter_swap(ip, iq); // ADL
    std::cout << *ip << ' ' << *iq << '\n';
 
    std::list x {0, 1, 3};
    std::counted_iterator<std::list<int>::iterator> ix { x.begin(), 2 };
//  iter_swap(ip, ix); // error: not indirectly swappable
}

Output:

1 5
5 1

[edit] See also

swaps the values of two objects
(function template) [edit]
swaps two ranges of elements
(function template) [edit]
swaps the elements pointed to by two iterators
(function template) [edit]
(C++20)
swaps the values referenced by two dereferenceable objects
(customization point object) [edit]
(C++20)
casts the result of dereferencing the underlying iterator to its associated rvalue reference type
(function) [edit]