How to use the remove, begin, and end STL functions in Visual C++

MORE INFORMATION

Required header

   <algorithm>

Prototype

   template<class ForwardIterator, class Type> inline
   ForwardIterator remove(ForwardIterator first,

                          ForwardIterator last,
                          const T& 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 remove algorithm removes all elements that match value from the range (first, last). It returns an iterator equal to last - N, where N = number of elements removed. The last N elements of the range have undefined values. The size of the container remains the same.

Sample code

////////////////////////////////////////////////////////////////////// 
// 
// Compile options needed: /GX
// 
// remove.cpp : Illustrates how to use the remove function.
// 
// Functions:
// 
//   remove - remove all elements from the sequence that match value.
//   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>
#include <functional>
using namespace std;

#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, last;

    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 remove" << endl ;

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

    // remove all elements from Numbers that match 10
     last = remove(start, end, 10) ;

    cout << "After calling remove" << endl ;

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

    //print number of elements removed from Numbers
    cout << "Total number of elements removed from Numbers = "
        << end - last << endl ;

    //print only the valid elements of Number
    cout << "Valid elements of Numbers { " ;
    for(it = start; it != last; it++)
        cout << *it << " " ;
    cout << " }\n" << endl ;

}

Program Output is:

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

After calling remove
Numbers { 20 15 12 7 9 7 9 10  }

Total number of elements removed from Numbers = 3
Valid elements of Numbers { 20 15 12 7 9  }