std::default_sentinel_t, std::default_sentinel

 

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indirectly_movable (C++20) indirectly_movable_storable (C++20) indirectly_copyable (C++20)	indirectly_copyable_storable (C++20)   indirectly_swappable (C++20) indirectly_comparable (C++20)	permutable (C++20) mergeable (C++20) sortable (C++20)
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reverse_iterator make_reverse_iterator (C++14) move_iterator (C++11) make_move_iterator (C++11) default_sentinel_tdefault_sentinel (C++20)(C++20) unreachable_sentinel_tunreachable_sentinel (C++20)(C++20)	front_insert_iterator back_insert_iterator inserter insert_iterator front_inserter back_inserter move_sentinel (C++20)	common_iterator (C++20) counted_iterator (C++20) basic_const_iterator (C++23) const_iterator (C++23) const_sentinel (C++23) make_const_iterator (C++23) make_const_sentinel (C++23)
Stream iterators istream_iterator    ostream_iterator istreambuf_iterator ostreambuf_iterator	Iterator customization points ranges::iter_move (C++20) ranges::iter_swap (C++20)
Iterator operations advance distance prev (C++11)   next (C++11) ranges::advance (C++20) ranges::distance (C++20) ranges::prev (C++20) ranges::next (C++20)	Range access begincbegin (C++11)(C++14) rbegincrbegin (C++14)(C++14)   endcend (C++11)(C++14) rendcrend (C++14)(C++14)   sizessize (C++17)(C++20) empty (C++17) data (C++17)

 

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

Run this code

#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());
}

See More

Output:

Found 3 words:
Quick
brown
fox.

See also

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)