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std::ranges::view_interface::operator[](3) | C++ Standard Libary | std::ranges::view_interface::operator[](3) |
NAME¶
std::ranges::view_interface::operator[] - std::ranges::view_interface::operator[]
Synopsis¶
template<ranges::random_access_range R = D>
constexpr decltype(auto) operator[]( ranges::range_difference_t<R>
(1) (since C++20)
n );
template<ranges::random_access_range R = const D>
constexpr decltype(auto) operator[]( ranges::range_difference_t<R>
(2) (since C++20)
n ) const;
The default implementation of operator[] member function obtains the element
at the
specified offset relative to the beginning iterator, reusing the operator[]
of the
iterator type.
1) Let derived be static_cast<D&>(*this). Equivalent to return
ranges::begin(derived)[n];.
2) Same as (1), except that derived is static_cast<const
D&>(*this).
Parameters¶
n - position of the element to return
Return value¶
The element at offset n relative to the beginning iterator.
Notes¶
In C++20, no type derived from std::ranges::view_interface in the
standard library
provides their own operator[] member function.
However, following derived types cannot use the default implementations, as
they
never satisfy random_access_range:
* std::ranges::basic_istream_view
* std::ranges::filter_view
* std::ranges::join_view
* std::ranges::lazy_split_view
* std::ranges::split_view
The inherited operator[] member function is available for
std::ranges::empty_view,
but a call to it always results in undefined behavior.
Example¶
This section is incomplete
Reason: no example
Category:¶
* Todo no example
2024.06.10 | http://cppreference.com |