||Component type: type
Random_access_iterator is an iterator base class: it is intended that an
iterator that is a model of Random Access Iterator, and whose value type
and distance type are T and Distance, may be defined by inheriting from
random_access_iterator<T, Distance> . Random_access_iterator is entirely empty: it has no
member functions, member variables, or nested types. It exists solely
to simplify the definition of the functions iterator_category,
distance_type, and value_type.
class my_random_access_iterator : public random_access_iterator<double>
This declares my_random_access_iterator to be a Random Access Iterator whose
value type is double and whose distance type is ptrdiff_t.
If Iter is an object of class my_random_access_iterator, then
iterator_category(Iter) will return random_access_iterator_tag(),
value_type(Iter) will return (double*) 0, and distance_type(Iter)
will return (ptrdiff_t*) 0.
Defined in the standard header iterator, and in the
nonstandard backward-compatibility header iterator.h.
This class is no longer part of the C++ standard, although
it was present in early drafts of the standard. It is retained
in this implementation for backward compatibility.
The iterator's value type
The iterator's distance type
Public base classes
The distance type must be a signed integral type.
Public base classes
It is not required that a Random Access Iterator inherit from
the base random_access_iterator. It is, however, required that the
functions iterator_category, distance_type, and
value_type be defined for every Random Access Iterator.
(Or, if you are using the iterator_traits mechanism, that
iterator_traits is properly specialized for every
Random Access Iterator.) Since those functions are defined for
the base random_access_iterator, the easiest way to ensure that are
defined for a new type is to derive that class from
random_access_iterator and rely on the derived-to-base standard
conversion of function arguments.
The Iterator Tags overview, iterator_traits,
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