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std::span<T,Extent>::rbegin, std::span<T,Extent>::crbegin

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< cpp‎ | container‎ | span
Revision as of 00:25, 6 July 2018 by Milkpot (Talk | contribs)

 
 
 
 
constexpr reverse_iterator rbegin() const noexcept;
(1) (since C++20)
constexpr const_reverse_iterator crbegin() const noexcept;
(2) (since C++23)

Returns a reverse iterator to the first element of the reversed span. It corresponds to the last element of the non-reversed span. If the span is empty, the returned iterator is equal to rend().

range-rbegin-rend.svg

Contents

Parameters

(none)

Return value

Reverse iterator to the first element.

Complexity

Constant.

Notes

The underlying iterator of the returned reverse iterator is the end iterator. Hence the returned iterator is invalidated if and when the end iterator is invalidated.

Example

#include <algorithm>
#include <iostream>
#include <iterator>
#include <span>
 
int main()
{
    constexpr std::span<const char> code{"@droNE_T0P_w$s@s#_SECRET_a,p^42!"};
 
    auto hack = [](const unsigned O) { return O - 0141 < 120; };
 
    std::copy_if(code.rbegin(), code.rend(),
        std::ostream_iterator<const char>(std::cout), hack);
 
    std::cout << '\n';
}

Output:

password

See also

(C++23)
returns a reverse iterator to the end
(public member function) [edit]
returns a reverse iterator to the beginning of a container or array
(function template) [edit]