Name

find_first_of function template — Searches for any one of a sequence of values

Synopsis

template<typename FwdIter1, typename FwdIter2>
  FwdIter1 find_first_of(FwdIter1 first1, FwdIter1 last1, FwdIter2 first2,
                         FwdIter2 last2);
template<typename FwdIter1, typename FwdIter2, typename BinaryPredicate>
  FwdIter1 find_first_of(FwdIter1 first1, FwdIter1 last1, FwdIter2 first2,
                         FwdIter2 last2, BinaryPredicate pred);

The find_first_of function template searches the range [first1, last1) for any one of the items in [first2, last2). If it finds a matching item, it returns an iterator that points to the matching item, in the range [first1, last1). It returns last1 if no matching item is found. Figure 13-6 shows an example.

Finding any one of a list of items
Figure 13-6. Finding any one of a list of items

The first form compares items with the == operator. The second form calls pred(*iter1, *iter2).

Technical Notes

Let length1 = last1 - first1 and length2 = last2 - first2.

The find_first_of function template returns first1 + n where n is the smallest value in the range [0, length1) such that *(first1 + n) == (first2 + m) for some m in the range [0, length2). It returns last1 if no such n and m can be found.

Complexity: at most length1 × length2 comparisons are performed.

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