std::ranges::view_interface<D>::operator[]

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< cpp‎ | ranges‎ | view interface
Ranges library
Range adaptors
template < ranges::random_access_range R = D>
constexpr decltype( auto ) operator[ ] ( ranges::range_difference_t <R> n ) ;
(1) (since C++20)
template < ranges::random_access_range R = const D>
constexpr decltype( auto ) operator[ ] ( ranges::range_difference_t <R> n ) const ;
(2) (since C++20)

The default implementation of operator[] member function obtains the element at the specified offset relative to the beginning iterator, reusing the operator[]

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[]

However, following derived types cannot use the default implementations, as they never satisfy random_access_range:

The inherited operator[] member function is available for std::ranges::empty_view

Example