std::ranges::crbegin
| Defined in header <ranges>
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| Defined in header <iterator>
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| inline namespace /* unspecified */ { inline constexpr /* unspecified */ crbegin = /* unspecified */; |
(since C++20) (customization point object) |
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| Call signature |
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| template< class T > requires /* see below */ |
(since C++20) | |
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Returns an iterator to the first element of the const-qualified argument that is treated as a reversed sequence. |
(until C++23) |
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Returns a constant iterator to the first element of the argument that is treated as a reversed sequence. |
(since C++23) |
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Let
A call to |
(until C++23) |
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If the argument is an lvalue or ranges::enable_borrowed_range<std::remove_cv_t<T>> is true, then a call to
In all other cases, a call to |
(since C++23) |
The return type models std::input_or_output_iterator and constant-iterator(since C++23) in all cases.
Customization point objects
The name ranges::crbegin denotes a customization point object, which is a const function object of a literal semiregular class type. See CustomizationPointObject for details.
[edit] Example
#include <cassert> #include <iterator> #include <span> #include <vector> int main() { std::vector<int> v{3, 1, 4}; auto vi = std::ranges::crbegin(v); assert(*vi == 4); ++vi; // OK, iterator object is mutable assert(*vi == 1); // *vi = 13; // Error: underlying element is read-only int a[]{-5, 10, 15}; auto ai = std::ranges::crbegin(a); assert(*ai == 15); // auto x_x = std::ranges::crbegin(std::vector<int>{6, 6, 6}); // ill-formed: the argument is an rvalue (see Notes ↑) auto si = std::ranges::crbegin(std::span{a}); // OK assert(*si == 15); static_assert ( std::ranges::enable_borrowed_range<std::remove_cv_t<decltype(std::span{a})>> ); }
[edit] See also
| (C++20) |
returns a reverse iterator to a range (customization point object) |
| (C++14) |
returns a reverse iterator to the beginning of a container or array (function template) |
