std::experimental::ranges::difference_type - cppreference.com
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| Defined in header |
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template< class I > struct difference_type {}; |
(1) | |
template< class T > struct difference_type<T*>; |
(2) | |
template< class T > struct difference_type<const T> : difference_type<std::decay_t<T>> {}; |
(3) | |
template< class T > requires requires { typename T::difference_type; } struct difference_type<T>; |
(4) | |
template< class T > requires !requires { typename T::difference_type; } && requires(const T& a, const T& b) { {a - b} -> Integral; } struct difference_type<T>; |
(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
template< class T > using difference_type_t = typename ranges::difference_type<T>::type; |
(ranges TS) | |