NAME¶

std::ranges::transform_view::iterator - std::ranges::transform_view::iterator

Synopsis¶

template< bool Const > (since C++20)
class /*iterator*/

The return type of transform_view::begin, and of transform_view::end when the
underlying view is a common_range.

The type /*iterator*/<true> is returned by the const-qualified overloads. The type
/*iterator*/<false> is returned by the non-const-qualified overloads.

The name of this class template (shown here as iterator) is unspecified.

Typical implementation holds two data members: an iterator into (possibly
const-qualified) V, and a pointer to parent transform_view.

Member types¶

Member type Definition
Parent (private) const ranges::transform_view<V, F> if Const is true, otherwise
ranges::transform_view<V, F>. The name is for exposition only.
Base (private) const V if Const is true, otherwise V. The name is for exposition
only.
std::random_access_iterator_tag if Base models
random_access_range,
iterator_concept std::bidirectional_iterator_tag if Base models
bidirectional_range,
std::forward_iterator_tag if Base models forward_range,
std::input_iterator_tag otherwise.
Not defined if Base does not model forward_range.
Otherwise, if std::invoke_result_t<F&,
ranges::range_reference_t<Base>> is not an lvalue reference,
std::input_iterator_tag.
iterator_category
Else, let C be
std::iterator_traits<ranges::iterator_t<Base>>::iterator_category.
If C is std::contiguous_iterator_tag, the type is
std::random_access_iterator_tag; otherwise, the type is C.
value_type std::remove_cvref_t<std::invoke_result_t<F&,
ranges::range_reference_t<Base>>>
difference_type ranges::range_difference_t<Base>

Member functions¶

constructor constructs an iterator
(C++20) (public member function)
base returns the underlying iterator
(C++20) (public member function)
operator* accesses the transformed element
(C++20) (public member function)
operator[] accesses an element by index
(C++20) (public member function)
operator++
operator++(int)
operator-- advances or decrements the underlying iterator
operator--(int) (public member function)
operator+=
operator-=
(C++20)

Non-member functions¶

operator==
operator<
operator> compares the underlying iterators
operator<= (function)
operator>=
operator<=>
(C++20)
operator+ performs iterator arithmetic
operator- (function)
(C++20)
iter_move obtains an rvalue reference to the transformed element
(C++20) (function)

Defect reports

The following behavior-changing defect reports were applied retroactively to
previously published C++ standards.

DR Applied to Behavior as published Correct behavior
P2259R1 C++20 member iterator_category is always defined only if Base models
defined forward_range
LWG 3555 C++20 the definition of iterator_concept made to consider
ignores const