Q156743: INFO: STL Sample for the replace_if Function

Article: Q156743
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 replace_if STL function in
Visual C++.

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

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

     <algorithm>

     template<class ForwardIterator, class Predicate, class Type> inline
     void replace_if(ForwardIterator first,

                     ForwardIterator last,
                     Predicate pred,
                     const Type& value)

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 replace_if algorithm replaces all elements from the range [first, last) that
cause the predicate to return true with value.

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
  // 
  // replace_if.cpp : Illustrates how to use the replace_if function.
  // 
  // Functions:
  // 
  //    replace_if - Replace all elements from the sequence that
  //                 satisfies a predicate with a specified value.
  // 
  // 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>
  #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 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

      //Initialize vector Numbers
      Numbers[0] = 10 ;
      Numbers[1] = 20 ;
      Numbers[2] = 10 ;
      Numbers[3] = 15 ;
      Numbers[4] = 12 ;
      Numbers[5] = 7 ;
      Numbers[6] = 9 ;
      Numbers[7] = 10 ;

      cout << "Before calling replace_if" << endl ;

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

      // replace all elements from Numbers that are <= 10 with 4
       replace_if(start, end, bind2nd(less_equal<int>(), 10), 4 ) ;

      cout << "After calling replace_if" << endl ;

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

  }

Program Output is:

Before calling replace_if
Numbers { 10 20 10 15 12 7 9 10  }

After calling replace_if
Numbers { 4 20 4 15 12 4 4 4  }

REFERENCES
==========

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

Additional query words: STL STLSample remove_if

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