std::default_sentinel_t, std::default_sentinel

Since C++20

Header: <iterator>

  1. default_sentinel_t is an empty class type used to denote the end of a range. It can be used together with iterator types that know the bound of their range (e.g., std::counted_iterator).

# Declarations

struct default_sentinel_t {};

(since C++20)

inline constexpr default_sentinel_t default_sentinel{};

(since C++20)

# Example

#include <algorithm>
#include <iostream>
#include <iterator>
#include <list>
 
int main()
{
    std::list<int> l{3, 1, 4, 1, 5, 9, 2, 6};
 
    std::ranges::copy(std::counted_iterator(std::begin(l), 4),
        std::default_sentinel, std::ostream_iterator<int>{std::cout, " "});
    std::cout << '\n';
}

# See also