std::ranges:: cend

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

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. 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

#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