View source for cpp/iterator/default sentinel t

{{cpp/title|default_sentinel_t|default_sentinel}}
{{cpp/iterator/navbar}}

{{dcl begin}}
{{dcl header|iterator}}
{{dcl|num=1|since=c++20|
struct default_sentinel_t {};
}}
{{dcl|num=2|since=c++20|
inline constexpr default_sentinel_t default_sentinel{};
}}
{{dcl end}}

@1@ {{tt|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., {{lc|std::counted_iterator}}).
@2@ {{tt|default_sentinel}} is a constant of type {{tt|default_sentinel_t}}.

===Example===
{{example
|code=
#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';
}
|output=3 1 4 1 
}}

===See also===
{{dsc begin}}
{{dsc inc|cpp/iterator/dsc istream_iterator}}
{{dsc inc|cpp/iterator/dsc istreambuf_iterator}}
{{dsc inc|cpp/iterator/dsc counted_iterator}}
{{dsc end}}

{{langlinks|ja|zh}}