Q156346: INFO: STL Sample for the iter_swap Function

Article: Q156346
Product(s): Microsoft C Compiler
Version(s): 4.2,5.0,6.0
Operating System(s): 
Keyword(s): kbcode kbVC420 kbVC500 kbVC600 kbDSupport
Last Modified: 26-MAR-2002

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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 iter_swap, begin, and end STL
function in Visual C++.

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

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

     <algorithm>

Prototype
---------

     template<class ForwardIterator1, class ForwardIterator2> inline

         void iter_swap(ForwardIterator1 first, ForwardIterator2 second)

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

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

The iter_swap algorithm swaps two elements represented by two iterators.

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

NOTE: In the first line of the sample code section, /GX is equivalent to /EHsc in
VC++ .NET and is set by default.

  ////////////////////////////////////////////////////////////////////// 
  // 
  // Compile options needed: /GX
  // 
  // iter_swap.cpp : Illustrates how to use the iter_swap function.
  // 
  // Functions:
  // 
  //   iter_swap  - Swap two elements in a sequence represented by
  //                two iterators.

  //   begin      - Returns an iterator that points to the first element
  //                in a sequence.

  //   end        - Returns an iterator that points one past the end of
                    a sequence.
  // 
  // Written by Kalindi Sanghrajka
  // of Microsoft Product Support Services,
  // Software Core Developer Support.
  // Copyright (c) 1996 Microsoft Corporation. All rights reserved.
  ////////////////////////////////////////////////////////////////////// 

  // disable warning C4786: symbol greater than 255 character,
  // okay to ignore

  #pragma warning(disable: 4786)

  #include <iostream>
  #include <vector>
  #include <algorithm>

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

  // return the next Fibonacci number in the
  // Fibonacci series.
  int Fibonacci(void)

  {

      static int r;
      static int f1 = 0;
      static int f2 = 1;
      r = f1 + f2 ;
      f1 = f2 ;
      f2 = r ;
      return f1 ;

  }

  void main()

  {

      const int VECTOR_SIZE = 8 ;

      // Define a template class vector of integers
      typedef vector<int, allocator<int> > IntVector ;

      //Define an iterator for template class vector of integer
      typedef IntVector::iterator IntVectorIt ;

      IntVector Numbers(VECTOR_SIZE) ;   //vector containing numbers

      IntVectorIt start, end, it ;

      start = Numbers.begin() ;   // location of first
                                  // element of Numbers

      end = Numbers.end() ;       // one past the location
                                  // last element of Numbers

      // fill the range [first, last +1) with a series of
      // Fibonacci numbers using the Fibonacci function
      generate(start, end, Fibonacci) ;

      cout << "Before calling iter_swap" << endl ;

      // print content of Numbers
      cout << "Numbers { " ;
      for(it = start; it != end; it++)
          cout << *it << " " ;
      cout << " }\n" << endl ;

      // swap the first and last elements of the
      // sequence using iter_swap
      iter_swap(start, end - 1) ;

      cout << "After calling iter_swap" << endl ;

      // print content of Numbers
      cout << "Numbers { " ;
      for(it = start; it != end; it++)
          cout << *it << " " ;
      cout << " }\n" << endl ;

  }

The Program Output is:

Before calling iter_swap
Numbers { 1 1 2 3 5 8 13 21  }

After calling iter_swap
Numbers { 21 1 2 3 5 8 13 1  }

REFERENCES
==========

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

Additional query words: STL STLSample generate end begin

======================================================================
Keywords          : kbcode kbVC420 kbVC500 kbVC600 kbDSupport 
Technology        : kbVCsearch kbAudDeveloper kbVCNET kbVCLibrary
Version           : :4.2,5.0,6.0
Issue type        : kbinfo

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