std::experimental::ranges::distance

Defined in header <experimental/ranges/iterator>
namespace { constexpr /* unspecified */ distance = /* unspecified */; }		(ranges TS) (customization point object)
Call signature
template < Iterator I, Sentinel<I> S > constexpr ranges:: difference_type_t <I> distance( I first, S last ) ;	(1)
template < Range R > constexpr ranges:: difference_type_t < ranges::iterator_t <R>> distance( R&& r ) ;	(2)
template < SizedRange R > constexpr ranges:: difference_type_t < ranges::iterator_t <R>> distance( R&& r ) ;	(3)

Returns the distance between first and last, or between the beginning and the end of the range r

Instantiating overloads (2,3) may be ill-formed if the header <experimental/ranges/range>

Customization point objects

The name ranges::distance denotes a customization point object, which is a function object of a literal Semiregular class type (denoted, for exposition purposes, as DistanceT). All instances of DistanceT are equal. Thus, ranges::distance

Given a set of types Args..., if std::declval <Args> ( ) meet the requirements for arguments to ranges::distance above, DistanceT will satisfy ranges::Invocable<const DistanceT, Args...> . Otherwise, no function call operator of DistanceT

In every translation unit in which ranges::distance is defined, it refers to the same instance of the customization point object. (This means that it can be used freely in things like inline functions and function templates without violating the one-definition rule

Return value

The distance between first and last, or between the beginning and the end of the range r

Example

This section is incomplete Reason: no example

See also

distance	returns the distance between two iterators (function template)
advance	advances an iterator by given distance (function template)
next	increment an iterator (function template)
prev	decrement an iterator (function template)
size	obtains the size of a range whose size can be calculated in constant time (customization point object)