Function template distance()

The boost::iterators::distance function template is an adapted version of std::distance for the Boost iterator traversal concepts.

<boost/iterator/distance.hpp>

template <typename Iterator>
constexpr typename iterator_difference<Iterator>::type
distance(Iterator first, Iterator last);

Computes the (signed) distance from first to last.

Iterator should model Single Pass Iterator.

If Iterator models Random Access Traversal Iterator, [first, last) or [last, first) should be valid; otherwise [first, last) should be valid.

If Iterator models Random Access Traversal Iterator, it takes constant time; otherwise it takes linear time.

This function is not a customization point and is protected against being found by argument-dependent lookup (ADL).
This function is constexpr only in C++14 or later.

Contributed by Michel Morin.