Search_n searches for a subsequence of count consecutive elements in the range [first, last), all of which are equal to value. [1] It returns an iterator pointing to the beginning of that subsequence, or else last if no such subsequence exists. The two versions of search_n differ in how they determine whether two elements are the same: the first uses operator==, and the second uses the user-supplied function object binary_pred.

The first version of search returns the first iterator i in the range [first, last – count) [2] such that, for every iterator j in the range [i, i + count), *j == value. The second version returns the first iterator i in the range [first, last – count) such that, for every iterator j in the range [i, i + count), binary_pred(*j, value) is true.