std::ranges::cend
<ranges>
<iterator>
inline constexpr /* unspecified */ cend = /* unspecified */;
(customization point object)
requires /* see below */
Returns a sentinel for the constant iterator(since C++23) indicating the end of a const-qualified(until C++23) range.
Let CT be
- const std::remove_reference_t <T>& if the argument is an lvalue (i.e.
Tis an lvalue reference type), - const T otherwise.
A call to ranges::cend is expression-equivalent to ranges::end (static_cast<CT&&>(t)).
If the argument is an lvalue or ranges::enable_borrowed_range <std::remove_cv_t <T>> is true, then a call to ranges::cend is expression-equivalent to:
- std::const_sentinel <decltype(U)>(U) for some expression U equivalent to ranges::end (
possibly-const-range(t)).
In all other cases, a call to ranges::cend is ill-formed, which can result in substitution failure when the call appears in the immediate context of a template instantiation.
If ranges::cend(e) is valid for an expression e, where decltype((e)) is T, then CT models std::ranges::range , and(until C++23) std::sentinel_for <S, I> is true in all cases, where S is decltype(ranges::cend(e)), and I is decltype(ranges::cbegin (e)). Additionally, S models constant-iterator if it models input_iterator.(since C++23)
Customization point objects
The name ranges::cend denotes a customization point object, which is a const function object of a literal semiregular class type. See CustomizationPointObject for details.
[edit] Example
#include <algorithm> #include <cassert> #include <ranges> #include <vector> int main() { std::vector vec{3, 1, 4}; int arr[]{5, 10, 15}; assert (std::ranges::find (vec, 5) == std::ranges::cend(vec)); assert (std::ranges::find (arr, 5) != std::ranges::cend(arr)); }