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std::iter_move(std::reverse_iterator)

From cppreference.com
 
 
Iterator library
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(C++20)
(C++20)
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(C++20)

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(C++11)    
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(C++11)(C++14)
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(C++17)
 
 
friend constexpr std::iter_rvalue_reference_t<Iter>
    iter_move( const std::reverse_iterator& i ) noexcept(/* see below */);
(since C++20)

Casts the result of dereferencing the adjusted underlying iterator to its associated rvalue reference type.

The function body is equivalent to:

auto tmp = i.base();
return std::ranges::iter_move(--tmp);

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

i - a source reverse iterator

[edit] Return value

An rvalue reference or a prvalue temporary.

[edit] Complexity

Constant.

[edit] Exceptions

noexcept specification:  
noexcept(

    std::is_nothrow_copy_constructible_v<Iter> &&
    noexcept(std::ranges::iter_move(--std::declval<Iter&>()))

)

[edit] Example

#include <iomanip>
#include <iostream>
#include <iterator>
#include <string>
#include <vector>
 
void print(auto const& rem, auto const& v)
{
    std::cout << rem << '[' << size(v) << "] {";
    for (char comma[]{0, 0}; auto const& s : v)
        std::cout << comma << ' ' << std::quoted(s), comma[0] = ',';
    std::cout << " }\n";
}
 
int main()
{
    std::vector<std::string> p{"Alpha", "Bravo", "Charlie"}, q;
 
    print("p", p), print("q", q);
 
    using RI = std::reverse_iterator<std::vector<std::string>::iterator>;
 
    for (RI iter{p.rbegin()}, rend{p.rend()}; iter != rend; ++iter)
        q.emplace_back(/* ADL */ iter_move(iter));
 
    print("p", p), print("q", q);
}

Possible output:

p[3] { "Alpha", "Bravo", "Charlie" }
q[0] { }
p[3] { "", "", "" }
q[3] { "Charlie", "Bravo", "Alpha" }

[edit] See also

(C++20)
casts the result of dereferencing an object to its associated rvalue reference type
(customization point object)[edit]
(C++20)
casts the result of dereferencing the underlying iterator to its associated rvalue reference type
(function) [edit]
(C++11)
obtains an rvalue reference
(function template) [edit]
obtains an rvalue reference if the move constructor does not throw
(function template) [edit]
(C++11)
forwards a function argument
(function template) [edit]
moves a range of elements to a new location
(niebloid)[edit]
moves a range of elements to a new location in backwards order
(niebloid)[edit]