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std::ranges:: cend

From cppreference.net
C++
Ranges library
Range adaptors
Defined in header <ranges>
Defined in header <iterator>
inline namespace /* unspecified */ {

inline constexpr /* unspecified */ cend = /* unspecified */ ;

}
(since C++20)
(customization point object)
Call signature
template < class T >

requires /* see below */

constexpr /* see below */ auto cend ( T && t ) ;
(since C++20)

Returns a sentinel for the constant iterator (since C++23) indicating the end of a const-qualified (until C++23) range.

range-begin-end.svg

Let CT be

A call to ranges::cend is expression-equivalent to ranges:: end ( static_cast < CT && > ( t ) ) .

(until C++23)

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:

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.

(since C++23)

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.

Example

Run this code 
#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));
}

See also

(C++20)
returns a sentinel indicating the end of a range
(customization point object)
(C++11) (C++14)
returns an iterator to the end of a container or array
(function template)