std::ranges::cend(3)

NAME
std::ranges::cend - std::ranges::cend

Synopsis
   Defined in header <ranges>
   inline namespace /*unspecified*/ {
                        (since C++20)
   inline constexpr /*unspecified*/ cend = /*unspecified*/; (customization point
                        object)
   }
   Call signature
   template< class T >
   requires /* see below */ (since C++20)
   constexpr std::sentinel_for<ranges::iterator_t<T>> auto cend(
   T&& t );
   Returns a sentinel indicating the end of a const-qualified range.
   range-begin-end.svg
   Let CT be
    1. const std::remove_reference_t<T>& if the argument is a lvalue (i.e. T is an
       lvalue reference type),
    2. const T otherwise,
   a call to ranges::cend is expression-equivalent to
   ranges::end(static_cast<CT&&>(t)).
   If ranges::cend(e) is valid for an expression e, where decltype((e)) is T, then CT
   models std::ranges::range, and std::sentinel_for<S, I> is true in all cases, where S
   is decltype(ranges::cend(e)), and I is decltype(ranges::cbegin(e)).
  Expression-equivalent
   Expression e is expression-equivalent to expression f, if
     * e and f have the same effects, and
     * either both are constant subexpressions or else neither is a constant
       subexpression, and
     * either both are potentially-throwing or else neither is potentially-throwing
       (i.e. noexcept(e) == noexcept(f)).
  Customization point objects
   The name ranges::cend denotes a customization point object, which is a const
   function object of a literal semiregular class type. For exposition purposes, the
   cv-unqualified version of its type is denoted as __cend_fn.
   All instances of __cend_fn are equal. The effects of invoking different instances of
   type __cend_fn on the same arguments are equivalent, regardless of whether the
   expression denoting the instance is an lvalue or rvalue, and is const-qualified or
   not (however, a volatile-qualified instance is not required to be invocable). Thus,
   ranges::cend can be copied freely and its copies can be used interchangeably.
   Given a set of types Args..., if std::declval<Args>()... meet the requirements for
   arguments to ranges::cend above, __cend_fn models
     * std::invocable<__cend_fn, Args...>,
     * std::invocable<const __cend_fn, Args...>,
     * std::invocable<__cend_fn&, Args...>, and
     * std::invocable<const __cend_fn&, Args...>.
   Otherwise, no function call operator of __cend_fn participates in overload
   resolution.

Example
// Run this code
 #include <algorithm>
 #include <iostream>
 #include <ranges>
 #include <vector>
 int main()
 {
     std::vector<int> v = { 3, 1, 4 };
     namespace ranges = std::ranges;
     if (ranges::find(v, 5) != ranges::cend(v)) {
         std::cout << "found a 5 in vector v!\n";
     }
     int a[] = { 5, 10, 15 };
     if (ranges::find(a, 5) != ranges::cend(a)) {
         std::cout << "found a 5 in array a!\n";
     }
 }

Output:
 found a 5 in array a!

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