Microsoft KB Archive/157480

= INFO: STL Sample for the rotate_copy Function =

Article ID: 157480

Article Last Modified on 9/18/2003

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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>

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

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

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This article was previously published under Q157480

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SUMMARY
The sample code below illustrates how to use the rotate_copy STL function in Visual C++.

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Prototype
template<class ForwardIterator, class OutputIterator> inline OutputIterator rotate_copy(BidirectionalIterator first,

BidirectionalIterator middle, BidirectionalIterator last, OutputIterator result) 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 rotate_copy algorithm rotates the elements in the range [first, last), to the right by N positions (where N = middle - first), and copies the result into a sequence of the same size, starting at result. It returns an iterator positioned immediately after the last new element in the resulting sequence.

Note that the OutputIterator should be different from the sequence to be rotated. If they are the same, the result will depend on the implementation.

Sample Code
////////////////////////////////////////////////////////////////////// // // Compile options needed: /GX // // rotate_copy.cpp : Illustrates how to use the rotate_copy function. // // Functions: // //   rotate_copy - Rotate a sequence by n positions, copy the //                 results to another same sized 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
 * 5) 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 strings typedef vector<string, allocator > StrVector ;

//Define an iterator for template class vector of strings typedef StrVector::iterator StrVectorIt ;

StrVector Tongue_Twister(VECTOR_SIZE) ; StrVector Rotated_Twister(VECTOR_SIZE) ;

StrVectorIt start, middle, end, it, RTstart, RTend ;

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

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

middle = start + 3 ;               // start position for // rotating elements

RTstart = Rotated_Twister.begin ; // location of first // element of Rotated_Twister

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

//Initialize vector Tongue_Twister Tongue_Twister[0] = "she" ; Tongue_Twister[1] = "sells" ; Tongue_Twister[2] = "sea" ; Tongue_Twister[3] = "shells" ; Tongue_Twister[4] = "by"; Tongue_Twister[5] = "the"; Tongue_Twister[6] = "sea" ; Tongue_Twister[7] = "shore" ;

cout << "Before calling rotate_copy:\n" << endl ;

// print content of Tongue_Twister cout << "Try this Tongue Twister: " ; for(it = start; it != end; it++) cout << *it << " " ; cout << "\n\n" ;

// rotate the items in the vector Tongue_Twist to the right by   // 3 positions and copy the results to Rotated_Twister rotate_copy(start, middle, end, RTstart) ;

cout << "After calling rotate_copy:\n" << endl ;

// print content of Tongue_Twister cout << "Tongue_Twister: " ; for(it = start; it != end; it++) cout << *it << " " ; cout << "\n\n" ;

// print content of Rotated_Twister cout << "Now try the rotated Tongue Twister: " ; for(it = RTstart; it != RTend; it++) cout << *it << " " ; cout << "\n\n" ;

}

Program Output is:
Before calling rotate_copy:

Try this Tongue Twister: she sells sea shells by the sea shore

After calling rotate_copy:

Tongue_Twister: she sells sea shells by the sea shore

Now try the rotated Tongue Twister: shells by the sea shore she sells sea

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