std::default_sentinel_t, std::default_sentinel

 

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Defined in header <iterator>
struct default_sentinel_t {};	(1)	(since C++20)
inlineconstexpr 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(){conststd::string s ="Quick brown fox.";   conststd::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(conststd::smatch& match : words)std::println("{}", match.str());}

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)