std::experimental::ranges::difference_type
From cppreference.com
< cpp | experimental | ranges
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) |