Standard C++ LibraryCopyright 1996, Rogue Wave Software, Inc.

NAME

  find_first_of  - Finds the first occurrence of any value from one sequence
  in another sequence.

SYNOPSIS

  #include <algorithm>

  template <class ForwardIterator1, class ForwardIterator2>
  ForwardIterator1 find_first_of (ForwardIterator1 first1,
                                 ForwardIterator1 last1,
                                 ForwardIterator2 first2,
                                 ForwardIterator2 last2);

  template <class ForwardIterator1, class ForwardIterator2,
           class BinaryPredicate>
  ForwardIterator1 find_first_of (ForwardIterator1 first1,
                                 ForwardIterator1 last1,
                                 ForwardIterator2 first2,
                                 ForwardIterator2 last2,
                                 BinaryPredicate pred);

DESCRIPTION

  The find_first_of algorithm finds a the first occurrence of a value from a
  sequence, specified by first2, last2, in a sequence specified by first1,
  last1. The algorithm returns an iterator in the range [first1, last1) that
  points to the first matching element.  If the first sequence [first1,
  last1) does not contain any of the values in the second sequence,
  find_first_of returns last1.

  In other words, find_first_of  returns the first iterator i in the [first1,
  last1)such that for some integer j in  the  range  [first2, last2):the
  following conditions hold:

  *i == *j, pred(*i,*j) == true.

  Or find_first_of  returns last1 if no such iterator is found.

COMPLEXITY

  Two versions of the algorithm exist.  The first uses the equality operator
  as the default binary predicate, and the second allows you to specify a
  binary predicate.

  At most (last1 - first1)*(last2 - first2) applications of the corresponding
  predicate are done.

EXAMPLE

  //
  // find_f_o.cpp
  //
   #include <vector>
   #include <iterator>
   #include <algorithm>
   #include <iostream.h>

  int main()
   {
    typedef vector<int>::iterator iterator;
    int d1[10] = {0,1,2,2,3,4,2,2,6,7};
    int d2[2] = {6,4};
     //
     // Set up two vectors
     //
    vector<int> v1(d1,d1 + 10), v2(d2,d2 + 2);
     //
     // Try both find_first_of variants
     //
    iterator it1 =
       find_first_of(v1.begin(),v1.end(),v2.begin(),v2.end());
     find_first_of(v1.begin(),v1.end(),v2.begin(),v2.end(),
                  equal_to<int>());
     //
     // Output results
     //
    cout << "For the vectors: ";
    copy(v1.begin(),v1.end(),
         ostream_iterator<int,char>(cout," " ));
    cout << " and ";
    copy(v2.begin(),v2.end(),
         ostream_iterator<int,char>(cout," " ));
    cout << endl << endl
         << "both versions of find_first_of point to: "
         << *it1;

    return 0;
   }

  Output :
  For the vectors: 0 1 2 2 3 4 2 2 6 7  and 6 4
  both versions of find_first_of point to: 4

WARNINGS

  If your compiler does not support default template parameters then you need
  to always supply the Allocator template argument.  For instance you'll have
  to write:

  vector<int, allocator<int> >

  instead of:

  vector<int>

SEE ALSO

  Algorithms, adjacent_find, find, find_if, find_next, find_end

STANDARDS CONFORMANCE

  ANSI X3J16/ISO WG21 Joint C++ Committee



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