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

NAME

  mismatch  - Compares elements from two sequences and returns the first two
  elements that don't match each other.

SYNOPSIS

  #include <algorithm>

  template <class InputIterator1, class InputIterator2>
   pair<InputIterator1,InputIterator2>
    mismatch(InputIterator1 first1, InputIterator1 last1,
            InputIterator2 first2);

  template <class InputIterator1, class InputIterator2,
           class BinaryPredicate>
   pair<InputIterator1, Inputiterator2>
    mismatch(InputIterator first1, InputIterator1 last1,
            InputIterator2 first2,
            BinaryPredicate binary_pred);

DESCRIPTION

  The mismatch algorithm compares members of two sequences and returns two
  iterators (i and j) that point to the first location in each sequence where
  the sequences differ from each other.  Notice that the algorithm denotes
  both a starting position and an ending position for the first sequence, but
  denotes only a starting position for the second sequence.  mismatch assumes
  that the second sequence has at least as many members as the first
  sequence.  If the two sequences are identical, mismatch returns a pair of
  iterators that point to the end of the first sequence and the corresponding
  location at which the comparison stopped in the second sequence.

  The first version of mismatch checks members of a sequence for equality,
  while the second version lets you specify a comparison function.  The
  comparison function must be a binary predicate.

  The iterators i and j returned by mismatch are defined as follows:

  j  == first2  +  (i  -  first1)

  and i is the first iterator in the range [first1, last1) for which the
  appropriate one of the following conditions hold:

  !(*i  ==  *(first2  +  (i  -  first1)))

  or

  binary_pred(*i, *(first2 + (i - first1))) == false

  If all of the members in the two sequences match, mismatch returns a pair
  of last1 and first2 + (last1 - first1).

COMPLEXITY

  At most last1 - first1  applications of the corresponding predicate are
  done.

EXAMPLE

  //
  // mismatch.cpp
  //
   #include <algorithm>
   #include <vector>
   #include <iostream.h>

  int main(void)
   {
    typedef vector<int>::iterator  iterator;
    int d1[4] = {1,2,3,4};
    int d2[4] = {1,3,2,4};

     // Set up two vectors
    vector<int> vi1(d1,d1 + 4), vi2(d2,d2 + 4);

     // p1 will contain two iterators that point to the
     // first pair of elements that are different between
     // the two vectors
    pair<iterator, iterator> p1 = mismatch(vi1.begin(), vi1.end(),
                                          vi2.begin());

     // find the first two elements such that an element in the
     // first vector is greater than the element in the second
     // vector.
    pair<iterator, iterator> p2 = mismatch(vi1.begin(), vi1.end(),
                                         vi2.begin(),
                                         less_equal<int>());

     // Output results
    cout << *p1.first << ", " << *p1.second << endl;
    cout << *p2.first << ", " << *p2.second << endl;

    return 0;
   }
  Output :
  2, 3
  3, 2

WARNING

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

  vector<int, allocator<int> >

  instead of:

  vector<int>

STANDARDS CONFORMANCE

  ANSI X3J16/ISO WG21 Joint C++ Committee



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