operator-(std::reverse_iterator)

From cppreference.com

template< class Iterator >

typename reverse_iterator<Iterator>::difference_type
operator-( const reverse_iterator<Iterator>& lhs,

const reverse_iterator<Iterator>& rhs );
(until C++11)
template< class Iterator1, class Iterator2 >

auto operator-( const reverse_iterator<Iterator1>& lhs,
const reverse_iterator<Iterator2>& rhs

) -> decltype(rhs.base() - lhs.base());
(since C++11)
(until C++17)
template< class Iterator1, class Iterator2 >

constexpr auto operator-( const reverse_iterator<Iterator1>& lhs,
const reverse_iterator<Iterator2>& rhs

) -> decltype(rhs.base() - lhs.base());
(since C++17)

Returns the distance between two iterator adaptors.

Parameters

lhs, rhs - iterator adaptors to compute the difference of

Return value

rhs.base() - lhs.base()

Example