DOCUMENT:Q168046  29-APR-2002  [visualc]
TITLE   :HOWTO: STL Sample for [list::rbegin, rend, reverse, rev_iterator
PRODUCT :Microsoft C Compiler
PROD/VER::4.2,5.0,6.0
OPER/SYS:
KEYWORDS:kbcode kbVC420 kbVC500 kbVC600

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The information in this article applies to:

 - The Standard C++ Library, used with:
    - Microsoft Visual C++, 32-bit Enterprise Edition, versions 4.2, 5.0, 6.0 
    - Microsoft Visual C++, 32-bit Professional Edition, versions 4.2, 5.0, 6.0 
    - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
    - Microsoft Visual C++.NET (2002) 
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SUMMARY
=======

The sample code below illustrates how to use the [list::rbegin, list::rend,
list::reverse_iterator, list::reverse] STL function(s) in Visual C++.

NOTE: There are some differences in the implementation of the Standard C++
Library components in Visual C++ version 4.2 versus later revisions. The
relevant sections of code below compile conditionally based upon the value of
_MSC_VER.

MORE INFORMATION
================

Required Header
---------------

      <list>
      <string>
      <iostream>

Prototype
---------

      const_reverse_iterator rbegin() const;
      reverse_iterator rbegin();
      const_reverse_iterator rend() const;
      reverse_iterator rend();
      typedef reverse_bidirectional_iterator<iterator,
          value_type, reference, A::types<T>::pointer,
              difference_type> reverse_iterator;
      void reverse();

NOTE: The class/parameter names in the prototype may not match the version in the
header file. Some have been modified to improve readability.

Description
-----------

This example shows how to iteratate through a list backwards. It also shows how
to reverse a list.

Sample Code
-----------

      ////////////////////////////////////////////////////////////////////// 
      // 
      // Compile options needed: -GX
      // 
      // rev.cpp :  This example shows how to iteratate through a list
      //            backwards.  It also shows how to reverse a list.
      // 
      // Functions:
      // 
      //  list::rbegin
      //  list::rend
      //  list::reverse_iterator
      //  list::reverse
      // 
      // Written by Andrew Bradnan
      // Copyright (c) 1996 Microsoft Corporation. All rights reserved.
      ////////////////////////////////////////////////////////////////////// 
      #pragma warning(disable:4786)
      #include <list>
      #include <string>
      #include <iostream>
      using namespace std;

      #if _MSC_VER > 1020   // if VC++ version is > 4.2
      using namespace std;  // std c++ libs implemented in std
      #endif

      typedef list<string, allocator<string> > LISTSTR;

      // We use this object so that list::sort() can sort in a different
      // order.Normally greater<> is used.  We override it here to switch to
      // less.
      struct less_str : greater<string> {
         bool operator()(const string& _X, const string& _Y) const
            {return (_X < _Y); }
         };

      void main()
      {
         LISTSTR test;
         LISTSTR::iterator i;
         LISTSTR::reverse_iterator r;

         test.push_back("one");
         test.push_back("two");
         test.push_back("three");

         // one two three
         cout << "Forwards" << endl << " ";
         for (i = test.begin(); i != test.end(); ++i)
            cout << *i << " ";
         cout << endl;

         // three two one
         cout << "Backwards" << endl << " ";
         for (r = test.rbegin(); r != test.rend(); ++r)
            cout << *r << " ";
         cout << endl;

         // Switch the order
         test.reverse();

         // three two one
         cout << "Reversed" << endl << " ";
         for (i = test.begin(); i != test.end(); ++i)
            cout << *i << " ";
         cout << endl;

         // sort alphabetically (decending by default)
         test.sort();

         // two three one
         cout << "Sorted descending" << endl << " ";
         for (i = test.begin(); i != test.end(); ++i)
            cout << *i << " ";
         cout << endl;

         test.sort(less_str());

         // One three two
         cout << "Sorted ascending" << endl << " ";
         for (i = test.begin(); i != test.end(); ++i)
            cout << *i << " ";
         cout << endl;
      }

Program Output
--------------

   Forwards
    one two three
   Backwards
    three two one
   Reversed
    three two one
   Sorted descending
    one three two
   Sorted ascending
    two three one

REFERENCES
==========

Visual C++ Books On Line: Visual C++ Books:C/C++:Standard C++ Library Reference.

Additional query words: STL STLSample [list::rbegin, list::rend, list::reverse_iterator, list::reverse]

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Keywords          : kbcode kbVC420 kbVC500 kbVC600 
Technology        : kbVCsearch kbAudDeveloper kbVCLibrary
Version           : :4.2,5.0,6.0
Issue type        : kbhowto

=============================================================================

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