std::experimental::ranges::iterator_category
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< cpp | experimental | ranges
Defined in header <experimental/ranges/iterator>
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template
<
class I >
struct iterator_category { } ; |
(1) | |
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template
<
class T >
struct iterator_category<T* > ; |
(2) | |
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template
<
class T >
struct iterator_category< const T> : iterator_category<T> { } ; |
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template
<
class T >
requires requires { typename T::iterator_category; } |
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Computes the iterator category of the class I, if any. Users may specialize iterator_category for a program-defined type.
1) Primary template is an empty struct.
2) Specialization for pointers. If
T is an object type, provides a member type type equal to ranges::random_access_iterator_tag. Otherwise, there is no member type
3) Specialization for const-qualified types.
4) Specialization for types that define a public and accessible member type
iterator_category. If T::iterator_category is the same as or derived from one of iterator category tags in namespace std, it is mapped to the corresponding tag in the namespace ranges as described below. Otherwise, provides a member type type equal to T::iterator_category.
- If
T::iterator_categoryis the same as or derives from std::random_access_iterator_tag, provides a member typetypeequal to ranges::random_access_iterator_tag - Otherwise, if
T::iterator_categoryis the same as or derives from std::bidirectional_iterator_tag, provides a member typetypeequal to ranges::bidirectional_iterator_tag - Otherwise, if
T::iterator_categoryis the same as or derives from std::forward_iterator_tag, provides a member typetypeequal to ranges::forward_iterator_tag - Otherwise, if
T::iterator_categoryis the same as or derives from std::input_iterator_tag, provides a member typetypeequal to ranges::input_iterator_tag - Otherwise, if
T::iterator_categoryis the same as or derives from std::output_iterator_tag, there is no membertype
Helper alias template
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template
<
class T >
using iterator_category_t = typename ranges:: iterator_category <T> :: type ; |
(ranges TS) | |
Example
| This section is incomplete Reason: no example |
See also
| empty class types used to indicate iterator categories (class) |
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| empty class types used to indicate iterator categories (class) |
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| compatibility traits class that collects an iterator’s associated types (alias template) |