STL Sample for the remove Function

ID: Q156531

The information in this article applies to:

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

SUMMARY

The sample code below illustrates 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)

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

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

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 }

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 begin end

Keywords          : kbcode STLIss 
Version           : WINNT:4.2;
Platform          : NT WINDOWS
Issue type        : kbhowto

Last Reviewed: October 10, 1997