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

NAME

  set_symmetric_difference  - Basic set operation for sorted sequences.

SYNOPSIS

  #include <algorithm>

  template <class InputIterator1, class InputIterator2,
           class OutputIterator>
  OutputIterator
  set_symmetric_difference (InputIterator1 first1,
                           InputIterator1 last1,
                           InputIterator2 first2,
                           InputIterator2 last2,
                           OutputIterator result);

  template <class InputIterator1, class InputIterator2,
           class OutputIterator, class Compare>
  OutputIterator
  set_symmetric_difference (InputIterator1 first1,
                           InputIterator1 last1,
                           InputIterator2 first2,
                           InputIterator2 last2,
                           OutputIterator result, Compare comp);

DESCRIPTION

  set_symmetric_difference constructs a sorted symmetric difference of the
  elements from the two ranges.  This means that the constructed range
  includes copies of the elements that are present in the range [first1,
  last1) but not present in the range [first2, last2)and copies of the
  elements that are present in the range [first2, last2) but not in the range
  [first1, last1).  It returns the end of the constructed range.

  For example, suppose we have two sets:

  1 2 3 4 5

  and

  3 4 5 6 7

  The set_symmetric_difference of these two sets is:

  1 2 6 7

  The result of set_symmetric_difference is undefined if the result range
  overlaps with either of the original ranges.

  set_symmetric_difference assumes that the ranges are sorted using the
  default comparison operator less than (<), unless an alternative comparison
  operator (comp) is provided.

  Use the set_symmetric_difference algorithm to return a result that includes
  elements that are present in the first set and not in the second.

COMPLEXITY

  At most ((last1 - first1) + (last2 - first2)) * 2 -1  comparisons are
  performed.

EXAMPLE

  //
  // set_s_di.cpp
  //
   #include<algorithm>
   #include<set>
   #include <istream.h>

  int main()
   {

     //Initialize some sets
    int a1[] = {1,3,5,7,9,11};
    int a3[] = {3,5,7,8};
    set<int, less<int> > odd(a1,a1+6), result,
                         small(a3,a3+4);

     //Create an insert_iterator for result
    insert_iterator<set<int, less<int> > >
                  res_ins(result, result.begin());

     //Demonstrate set_symmetric_difference
    cout << "The symmetric difference of:" << endl << "{";
    copy(small.begin(),small.end(),
         ostream_iterator<int,char>(cout," "));
    cout << "} with {";
    copy(odd.begin(),odd.end(),
         ostream_iterator<int,char>(cout," "));
    cout << "} =" << endl << "{";
     set_symmetric_difference(small.begin(), small.end(),
                        odd.begin(), odd.end(), res_ins);
    copy(result.begin(),result.end(),
         ostream_iterator<int,char>(cout," "));
    cout << "}" << endl << endl;

    return 0;
   }

  Output :
  The symmetric difference of:
  {3 5 7 8 } with {1 3 5 7 9 11 } =
  {1 8 9 11 }

WARNING

  If your compiler does not support default template parameters, then you
  need to always supply the Compare template argument and the Allocator
  template argument. For instance, you will need to write :

  set<int, less<int>, allocator<int> >

  instead of :

  set<int>

SEE ALSO

  includes, set, set_union, set_intersection, set_difference

STANDARDS CONFORMANCE

  ANSI X3J16/ISO WG21 Joint C++ Committee



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