std::default_sentinel_t, std::default_sentinel

Defined in header `<iterator>`
struct default_sentinel_t {};	(1)	(since C++20)
inline constexpr default_sentinel_t default_sentinel{};	(2)	(since C++20)

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).

2) default_sentinel is a constant of type default_sentinel_t.

Example

#include <print>
#include <regex>
#include <string>

int main()
{
    const std::string s = "Quick brown fox.";

    const std::regex words_regex("[^\\s]+");
    const std::ranges::subrange words(
        std::sregex_iterator(s.begin(), s.end(), words_regex), std::default_sentinel);

    std::println("Found {} words:", std::ranges::distance(words));
    for (const std::smatch& match : words)
        std::println("{}", match.str());
}

Output:

Found 3 words:
Quick
brown
fox.

istream_iterator	input iterator that reads from `std::basic_istream` (class template)
istreambuf_iterator	input iterator that reads from `std::basic_streambuf` (class template)
counted_iterator (C++20)	iterator adaptor that tracks the distance to the end of the range (class template)

std::default_sentinel_t, std::default_sentinel

Example

See also