C++ In a Nutshell

Name

includes function template — Tests sorted ranges for subset

Synopsis

template<typename InIter1, typename InIter2>
  bool includes(InIter1 first1, InIter1 last1, InIter2 first2, InIter2 last2);
template<typename InIter1, typename InIter2, typename Compare> 
  bool includes(InIter1 first1, InIter1 last1, InIter2 first2, InIter2 last2,
                Compare comp);

The includes function template checks for a subset relationship, that is, it returns true if every element in the sorted sequence [first2, last2) is contained in the sorted sequence [first1, last1). It returns false otherwise.

Both sequences must be sorted. The first form uses the < operator to compare the elements. The second form calls comp(*iter1, *iter2).

Technical Notes

Precondition: !(*(i + 1) < *i) for all i in [first1, last1 - 1) and !(*(j + 1) < *j) for all j in [first2, last2 - 1).

The includes function template returns true if there is an i in [first1, last1) such that *(i + n) = *(first2 + n) for all n in [0, (last2 - first2)). It returns last1 if there is no such i.

Complexity is linear: at most, 2 × ((last1 - first1) + (last2 - first2)) - 1 comparisons are performed.

See Also

set_difference function template, set_intersection function template, set_symmetric_difference function template, set_union function template