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Q156534: INFO: STL Sample for the remove_copy_if Function

Article: Q156534
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: 27-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 remove_copy_if, begin, end, and
bind2nd STL functions in Visual C++.

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

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

      <algorithm>

Prototype
---------

     template<class ForwardIterator, class OutputIterator, class Predicate>

         inline OutputIterator remove_copy_if(ForwardIterator first,
                                ForwardIterator last,
                                OutputIterator result,
                                Predicate pred)

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 remove_copy_if algorithm copies all elements from the range (first, last) to
the range starting at result, skipping any element that causes the predicate to
return true. It returns an iterator positioned immediately after the last new
element.

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

NOTE: The first line in the sample code section says:

  // Compile options needed: /GX

In VC++ .NET, /EHsc is set by default and is equivalent to /GX.

  ////////////////////////////////////////////////////////////////////// 
  // 
  // Compile options needed: /GX
  // 
  // remove_copy_if.cpp : Illustrates how to use the remove_copy_if function.
  // 
  // Functions:
  // 
  //   remove_copy_if - copy the elements of a sequence to another sequence
  //                    eliminating any elements that satisfy a predicate.
  //   bind2nd - Returns true for elements for which the condition is true
  //   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)

  // disable warning C4244: possible loss of data,
  // okay to ignore

  #pragma warning(disable: 4244)

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

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

  void main()

  {

      const int MAX_ELEMENTS = 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 ;

      //vector containing numbers
      IntVector Numbers(MAX_ELEMENTS), Result(MAX_ELEMENTS) ;

      IntVectorIt start, end, it, last, resultIt ;

      //Initialize vector Numbers
      Numbers[0] = 10 ;
      Numbers[1] = 20 ;
      Numbers[2] = 10 ;
      Numbers[3] = 15 ;
      Numbers[4] = 12 ;
      Numbers[5] = 25 ;
      Numbers[6] = 30 ;
      Numbers[7] = 10 ;

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

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

      resultIt = Result.begin() ; // location of first
                                  // element of Result

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

      // copy all elements from Numbers to Result
      // skipping any item that >= 25
      last = remove_copy_if(start, end, resultIt,
                            bind2nd(greater_equal<int>(), 25)) ;

      //print number of elements copied to Result
      cout << "Total number of elements copied to Result = "
          << last - resultIt << endl ;

      start = Result.begin() ;   // location of first
                                  // element of Result
  >
      end = Result.end() ;       // one past the location
                                 // last element of Result

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

  }

Program Output is:

Numbers { 10 20 10 15 12 25 30 10  }

Total number of elements copied to Result = 6
Result { 10 20 10 15 12 10 0 0  }

REFERENCES
==========

Visual C++, version 4.2, Visual C++ Books Online; click Visual C++ Books, C/C++,
and then Standard C++ Library Reference.

Additional query words: STL STLSample remove_copy_if bind2nd begin end

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

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

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