std::span<T,Extent>::rend, std::span<T,Extent>::crend

 

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span::rbeginspan::crbegin (C++23)

span::rendspan::crend (C++23)

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dynamic_extent

Deduction guides

 

constexpr reverse_iterator rend() const noexcept;	(1)	(since C++20)
constexpr const_reverse_iterator crend() const noexcept;	(2)	(since C++23)

Returns a reverse iterator to the element following the last element of the reversed span. It corresponds to the element preceding the first element of the non-reversed span. This element acts as a placeholder, attempting to access it results in undefined behavior.

Parameters

(none)

Return value

Reverse iterator to the element following the last element.

Complexity

Constant.

Example

Run this code

#include <algorithm>
#include <iostream>
#include <span>
#include <string_view>
 
void ascending(const std::span<const std::string_view> data,
               const std::string_view term)
{
    std::for_each(data.begin(), data.end(),
        [](const std::string_view x) { std::cout << x << ' '; });
    std::cout << term;
}
 
void descending(const std::span<const std::string_view> data,
                const std::string_view term)
{
    std::for_each(data.rbegin(), data.rend(),
        [](const std::string_view x) { std::cout << x << ' '; });
    std::cout << term;
}
 
int main()
{
    constexpr std::string_view bars[]{"▁","▂","▃","▄","▅","▆","▇","█"};
    ascending(bars, " ");
    descending(bars, "\n");
}

Output:

▁ ▂ ▃ ▄ ▅ ▆ ▇ █  █ ▇ ▆ ▅ ▄ ▃ ▂ ▁

See also

rbegincrbegin (C++23)	returns a reverse iterator to the beginning (public member function)
rendcrend (C++14)	returns a reverse end iterator for a container or array (function template)