Microsoft KB Archive/156346

= INFO: STL Sample for the iter_swap Function =

Article ID: 156346

Article Last Modified on 9/23/2003

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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> </li> Microsoft Visual C++ .NET 2002 Standard Edition</li> Microsoft Visual C++ .NET 2003 Standard Edition</li></ul>

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This article was previously published under Q156346

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

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Prototype
template<class ForwardIterator1, class ForwardIterator2> inline

void iter_swap(ForwardIterator1 first, ForwardIterator2 second) 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 iter_swap algorithm swaps two elements represented by two iterators.

Sample Code
NOTE: In the first line of the sample code section, /GX is equivalent to /EHsc in VC++ .NET and is set by default. ////////////////////////////////////////////////////////////////////// // // Compile options needed: /GX // // iter_swap.cpp : Illustrates how to use the iter_swap function. // // Functions: // //  iter_swap  - Swap two elements in a sequence represented by //                two iterators.

//  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)


 * 1) include
 * 2) include
 * 3) include

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

// return the next Fibonacci number in the // Fibonacci series. int Fibonacci(void)

{

static int r;   static int f1 = 0; static int f2 = 1; r = f1 + f2 ; f1 = f2 ; f2 = r ; return f1 ;

}

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 ;

start = Numbers.begin ;  // location of first // element of Numbers

end = Numbers.end ;      // one past the location // last element of Numbers

// fill the range [first, last +1) with a series of   // Fibonacci numbers using the Fibonacci function    generate(start, end, Fibonacci) ;

cout << "Before calling iter_swap" << endl ;

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

// swap the first and last elements of the // sequence using iter_swap iter_swap(start, end - 1) ;

cout << "After calling iter_swap" << endl ;

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

} The Program Output is: <pre class="fixed_text">Before calling iter_swap Numbers { 1 1 2 3 5 8 13 21 }

After calling iter_swap Numbers { 21 1 2 3 5 8 13 1 }

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