std::ranges::view_interface<D>::front

constexpr decltype( auto ) front( )     requires ranges::forward_range <D> ;	(1)	(since C++20)
constexpr decltype( auto ) front( ) const     requires ranges::forward_range < const D> ;	(2)	(since C++20)

The default implementation of front() member function returns the first element in the view of the derived type. Whether the element is returned by value or by reference depends on the operator*

Parameters

(none)

Return value

The first element in the view.

Notes

In C++20, no type derived from std::ranges::view_interface in the standard library provides their own front()

A notable exception is std::ranges::basic_istream_view. For it never satisfies forward_range, the view cannot use the inherited front()

The inherited front() 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

See also

begincbegin (C++11)(C++14)	returns an iterator to the beginning of a container or array (function template)
ranges::begin (C++20)	returns an iterator to the beginning of a range (customization point object)
ranges::cbegin (C++20)	returns an iterator to the beginning of a read-only range (customization point object)