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Difference between revisions of "cpp/iterator/reverse iterator/iter swap"

From cppreference.com
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{{title | 1=<small>std::</small>iter_swap<small>(std::reverse_iterator)</small>}}
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{{title | iter_swap<small>(std::reverse_iterator)</small>}}
 
{{cpp/iterator/reverse_iterator/navbar}}
 
{{cpp/iterator/reverse_iterator/navbar}}
 
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template< std::indirectly_swappable<Iter> Iter2 >
 
template< std::indirectly_swappable<Iter> Iter2 >
 
   friend constexpr void
 
   friend constexpr void
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     std::iter_swap( const std::reverse_iterator& x,
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     iter_swap( const reverse_iterator& x,
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                    const std::reverse_iterator<Iter2>& y ) noexcept(/*see below*/);
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const std::reverse_iterator<Iter2>& y ) noexcept(/*see below*/);
 
}}
 
}}
 
{{dcl end}}
 
{{dcl end}}
  
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Swaps the objects pointed to by two adjusted underlying iterators. A call to this function is expression-equivalent to:  
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Swaps the objects pointed to by two adjusted underlying iterators. function is equivalent to:  
  
 
{{source|1=
 
{{source|1=
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ranges::iter_swap(--tmp_x, --tmp_y);
 
ranges::iter_swap(--tmp_x, --tmp_y);
 
}}
 
}}
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 +
  
 
===Parameters===
 
===Parameters===
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===Complexity===
 
===Complexity===
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constant
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−
 
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===Exception===
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<!-- {{cpp/impldef exception}} -->
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The expression in {{tt|noexcept}} is equivalent to:
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{{cc|
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std::is_nothrow_copy_constructible_v<Iter> &&
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{{|
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std::is_nothrow_copy_constructible_v<Iter2> &&
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std::is_nothrow_copy_constructible_v<Iter> &&
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noexcept(ranges::iter_swap(--std::declval<Iter&>(), --std::declval<Iter2&>()))
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std::is_nothrow_copy_constructible_v<Iter2> &&
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noexcept(ranges::iter_swap(--std::declval<Iter&>(), --std::declval<Iter2&>()))
 
}}
 
}}
  

Revision as of 04:32, 29 April 2021

 
C++
 
Iterator library
Iterator concepts
Iterator primitives
Algorithm concepts and utilities
Indirect callable concepts
Common algorithm requirements
(C++20)
(C++20)
(C++20)
Utilities
(C++20)
Iterator adaptors
Range access
(C++11)(C++14)
(C++14)(C++14)  
(C++11)(C++14)
(C++14)(C++14)  
(C++17)(C++20)
(C++17)
(C++17)
 
std::reverse_iterator
 
template< std::indirectly_swappable<Iter> Iter2 >

  friend constexpr void
    iter_swap( const reverse_iterator& x,

               const std::reverse_iterator<Iter2>& y ) noexcept(/*see below*/);
 (since C++20)

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.

Contents

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() };