Q168047: HOWTO: STL Sample for [list::remove, remove_if] Function(s)

Article: Q168047
Product(s): Microsoft C Compiler
Version(s): winnt:4.2,5.0,6.0
Operating System(s): 
Keyword(s): _IK kbVC420 kbVC500 kbVC600
Last Modified: 05-MAY-2001

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The information in this article applies to:

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

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

Note that 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
---------

     void remove(const T& x);
     void remove_if(binder2nd< not_equal_to<T> > pr);

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 use list::remove and list::remove_if. It also shows how
to use list::remove_if with your own function.

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

     ////////////////////////////////////////////////////////////////////// 
     // 
     // Compile options needed: -GX
     // 
     // remove.cpp :  This example shows how to use list::remove and
     //               list::remove_if.  It also shows how to use
     //               list::remove_if with your own function.
     // 
     // Functions:
     // 
     //  list::remove
     //  list::remove_if
     // 
     // Written by Andrew Bradnan
     // Copyright (c) 1996 Microsoft Corporation. All rights reserved.
     ////////////////////////////////////////////////////////////////////// 

     #pragma warning(disable:4786) // disable spurious C4786 warnings

     #include <list>
     #include <string>
     #include <iostream>
     using namespace std;

     #if _MSC_VER > 1020   // if later than revision 4.2
     using namespace std;   // std c++ libs are implemented in std
     #endif

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

     // Used to customize list::remove_if()
     class is_four_chars
        : public not_equal_to<string>
     {
        bool operator()(const string& rhs, const string&) const
        {  return rhs.size() == 4; }
     };

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

        test.push_back("good");
        test.push_back("bad");
        test.push_back("ugly");

        // good bad ugly
        for (i = test.begin(); i != test.end(); ++i)
           cout << *i << " ";
        cout << endl;

        test.remove("bad");

        // good ugly
        for (i = test.begin(); i != test.end(); ++i)
           cout << *i << " ";
        cout << endl;

        // remove any not equal to "good"
        test.remove_if(binder2nd<not_equal_to<string> >
           (not_equal_to<string>(), "good"));

        // good
        for (i = test.begin(); i != test.end(); ++i)
           cout << *i << " ";
        cout << endl;

        // Remove any strings that are four characters long
        test.remove_if(binder2nd<not_equal_to<string> >
           (is_four_chars(), "useless parameter"));

        if (test.empty())
           cout << "Empty list\n";

     }

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

  good bad ugly
  good ugly
  good
  Empty list

REFERENCES
==========

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

Additional query words: STL STLSample [xxxx]

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

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