Luna::set_difference

template <typename _InputIt1, typename _InputIt2, typename _OutputIt, typename _Compare>
_OutputIt set_difference(_InputIt1 first1, _InputIt1 last1, _InputIt2 first2, _InputIt2 last2, _OutputIt d_first, _Compare comp)

Copies elements that appear in the first sorted range and do not appear in the second sorted range to the destination range. The destination range is also sorted.

Parameters

• in first1

  The iterator to the first element of the first range.

• in last1

  The iterator to the one-past-last element of the first range.

• in first2

  The iterator to the first element of the second range.

• in last2

  The iterator to the one-past-last element of the second range.

• in d_first

  The iterator to the first element of the destination range.

• in comp

  The user-provided binary predicate which returns ​true if the first argument is less than the second.

Return value

Returns one iterator to the one-past-last element of the destination range.

Remark

If [first1, last1) contains m elements that are equivalent to each other and [first2, last2) contains n elements that are equivalent to them, the final max(m - n, 0) elements will be copied from [first1, last1) to the output range, preserving order.

Valid Usage

• Elements in the ranges specified by [first1, last1) and [first2, last2) must be sorted in non-descending order.

• comp must have the following function signature: bool comp(const Type& a, const Type& b), where Type is the value type of both _InputIt1 and _InputIt2.