rotate_copy (STL Samples)

Illustrates how to use the rotate_copy Standard Template Library (STL) function in Visual C++.

template<class ForwardIterator, class OutputIterator> inline
   OutputIterator rotate_copy(
      BidirectionalIterator First,
      BidirectionalIterator Middle,
      BidirectionalIterator Last,
      OutputIterator Result
   )

Remarks

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.

Example

// rotate_copy.cpp
// compile with: /EHsc
// 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.
//
//////////////////////////////////////////////////////////////////////

// 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>

using namespace std ;

int main()
{
   const int VECTOR_SIZE = 8 ;

   // Define a template class vector of strings
   typedef vector<string> 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 ;

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

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

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

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

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

   // 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:" << endl ;

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

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

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

Output

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

Requirements

Header: <algorithm>

See Also

Concepts

Standard Template Library Samples