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