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

• The Standard C++ Library included with: - Microsoft Visual C++, 32-bit Editions, version 4.2

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);

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>

   #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.