INFO: STL Sample for the rotate Function

ID: Q157479

The information in this article applies to:

The Standard C++ Library, used with:
- Microsoft Visual C++, 32-bit Editions, versions 4.2, 5.0, 6.0

SUMMARY

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

MORE INFORMATION

Required Header


   <algorithm>

Prototype


   template<class ForwardIterator> inline
   void rotate(ForwardIterator first,

               ForwardIterator middle,
               ForwardIterator last)

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 algorithm rotates the elements in the range [first, last), to the right by N positions, where N = middle - first.

Sample Code


////////////////////////////////////////////////////////////////////// 
// 
// Compile options needed: /GX
// 
// rotate.cpp : Illustrates how to use the rotate function.
// 
// Functions:
// 
//    rotate - Rotate the items in a sequence by n positions.
// 
// 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 <string>
#include <algorithm>
#include <functional>

#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 strings
    typedef vector<string, allocator<string> > StrVector ;

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

    StrVector Tongue_Twister(VECTOR_SIZE) ;

    StrVectorIt start, end, middle, it ;

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

    end = Tongue_Twister.end() ;       // one past the location last
                                       // element of Tongue_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" ;

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

    cout << "Before calling rotate\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_Twister by 3 positions
    rotate(start, middle, end) ;

    cout << "After calling rotate \n" << endl ;

    // print content of Tongue_Twister
    cout << "Now try the rotated Tongue Twister: " ;
    for(it = start; it != end; it++)
        cout << *it << " " ;
    cout << "\n\n" ;
}

Program Output is:

Before calling rotate

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

After calling rotate

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

REFERENCES

Visual C++ Books On Line: Visual C++ Books:C/C++:Standard C++ Library Reference.

Additional query words: STL STLSample rotate

Keywords : kbcode kbVC420 kbVC500 kbVC600 kbDSupport STLIss
Version : winnt:4.2,5.0,6.0
Platform : winnt
Issue type : kbinfo