std::experimental::ranges::difference_type
< cpp | experimental | ranges
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Defined in header
<experimental/ranges/iterator> |
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template< class I >
struct difference_type {}; |
(1) | |
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template< class T >
struct difference_type<T*>; |
(2) | |
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template< class T >
struct difference_type<const T> : difference_type<std::decay_t<T>> {}; |
(3) | |
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template< class T >
requires requires { typename T::difference_type; } |
(4) | |
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template< class T >
requires !requires { typename T::difference_type; } && |
(5) | |
Computes the associated difference type of the type I, if any. Users may specialize difference_type 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 std::ptrdiff_t. Otherwise, there is no member type.3) Specialization for const-qualified types.
4) Specialization for types that define a public and accessible member type
difference_type. Provides a member type type equal to T::difference_type.5) Specialization for types that do not define a public and accessible member type
difference_type but do support subtraction. Provides a member type type equal to std::make_signed_t<decltype(std::declval<T>() - std::declval<T>())>.Helper alias template
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template< class T >
using difference_type_t = typename ranges::difference_type<T>::type; |
(ranges TS) | |
Example
| This section is incomplete Reason: no example |
See also
specifies that a Semiregular type can be incremented with pre- and post-increment operators(concept) |
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| compatibility traits class that collects an iterator’s associated types (alias template) |