Microsoft KB Archive/156531

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

Article ID: 156531

Article Last Modified on 12/29/2005

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APPLIES TO

 The Standard C++ Library, when used with:  Microsoft Visual C++ 4.2 Enterprise Edition

 Microsoft Visual C++ 5.0 Enterprise Edition

 Microsoft Visual C++ 6.0 Enterprise Edition

 Microsoft Visual C++ 4.2 Professional Edition</li></ul>

 Microsoft Visual C++ 5.0 Professional Edition</li></ul>

 Microsoft Visual C++ 6.0 Professional Edition</li></ul>

 Microsoft Visual C++ 6.0 Standard Edition</li></ul>

 Microsoft Visual C++ .NET 2003 Standard Edition</li></ul>

 Microsoft Visual C++ .NET 2002 Standard Edition</li></ul>

 Microsoft Visual C++ 2005 Express Edition</li></ul> </li></ul>

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This article was previously published under Q156531

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Note Microsoft Visual C++ NET (2002) supported both the managed code model that is provided by the Microsoft .NET Framework and the unmanaged native Windows code model. The information in this article applies to unmanaged Visual C++ code only.

Note Microsoft Visual C++ NET 2005 supports both the managed code model that is provided by the .NET Framework and the unmanaged native Microsoft Windows code model.

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SUMMARY
The sample code below illustrates how to use the remove, begin, and end STL functions in Visual C++.

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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


 * 1) pragma warning(disable: 4786)

using namespace std;
 * 1) include
 * 2) include
 * 3) include
 * 4) include

using namespace std; // std c++ libs implemented in std #endif
 * 1) if _MSC_VER > 1020  // if VC++ version is > 4.2

void main

{

const int VECTOR_SIZE = 8 ;

// Define a template class vector of integers typedef vector<int, allocator > 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: <pre class="fixed_text">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 }

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