C++/STL Algorithms Modifying sequence operations/rotate

Use rotate to rotate one element to the left

<source lang="cpp">

/* The following code example is taken from the book

* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/

1. include <iostream>
2. include <vector>
3. include <deque>
4. include <list>
5. include <set>
6. include <map>
7. include <string>
8. include <algorithm>
9. include <iterator>
10. include <functional>
11. include <numeric>

/* PRINT_ELEMENTS()

* - prints optional C-string optcstr followed by
* - all elements of the collection coll
* - separated by spaces
*/

template <class T> inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="") {

   typename T::const_iterator pos;
   std::cout << optcstr;
   for (pos=coll.begin(); pos!=coll.end(); ++pos) {
       std::cout << *pos << " ";
   }
   std::cout << std::endl;

} /* INSERT_ELEMENTS (collection, first, last)

* - fill values from first to last into the collection
* - NOTE: NO half-open range
*/

template <class T> inline void INSERT_ELEMENTS (T& coll, int first, int last) {

   for (int i=first; i<=last; ++i) {
       coll.insert(coll.end(),i);
   }

} using namespace std; int main() {

   vector<int> coll;
   INSERT_ELEMENTS(coll,1,9);
   PRINT_ELEMENTS(coll,"coll:      ");
   // rotate one element to the left
   rotate (coll.begin(),      // beginning of range
           coll.begin() + 1,  // new first element
           coll.end());       // end of range
   PRINT_ELEMENTS(coll,"one left:  ");

} /* coll: 1 2 3 4 5 6 7 8 9 one left: 2 3 4 5 6 7 8 9 1

*/        
 </source>

Use rotate to rotate so that element with value 4 is the beginning

<source lang="cpp">

/* The following code example is taken from the book

* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/

1. include <iostream>
2. include <vector>
3. include <deque>
4. include <list>
5. include <set>
6. include <map>
7. include <string>
8. include <algorithm>
9. include <iterator>
10. include <functional>
11. include <numeric>

/* PRINT_ELEMENTS()

* - prints optional C-string optcstr followed by
* - all elements of the collection coll
* - separated by spaces
*/

template <class T> inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="") {

   typename T::const_iterator pos;
   std::cout << optcstr;
   for (pos=coll.begin(); pos!=coll.end(); ++pos) {
       std::cout << *pos << " ";
   }
   std::cout << std::endl;

} /* INSERT_ELEMENTS (collection, first, last)

* - fill values from first to last into the collection
* - NOTE: NO half-open range
*/

template <class T> inline void INSERT_ELEMENTS (T& coll, int first, int last) {

   for (int i=first; i<=last; ++i) {
       coll.insert(coll.end(),i);
   }

} using namespace std; int main() {

   vector<int> coll;
   INSERT_ELEMENTS(coll,1,9);
   PRINT_ELEMENTS(coll,"coll:      ");
   // rotate so that element with value 4 is the beginning
   rotate (coll.begin(),                     // beginning of range
           find(coll.begin(),coll.end(),4),  // new first element
           coll.end());                      // end of range
   PRINT_ELEMENTS(coll,"4 first:   ");

} /* coll: 1 2 3 4 5 6 7 8 9 4 first: 4 5 6 7 8 9 1 2 3

*/
       
 </source>

Use rotate to rotate two elements to the right

<source lang="cpp">

/* The following code example is taken from the book

* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/

1. include <iostream>
2. include <vector>
3. include <deque>
4. include <list>
5. include <set>
6. include <map>
7. include <string>
8. include <algorithm>
9. include <iterator>
10. include <functional>
11. include <numeric>

/* PRINT_ELEMENTS()

* - prints optional C-string optcstr followed by
* - all elements of the collection coll
* - separated by spaces
*/

template <class T> inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="") {

   typename T::const_iterator pos;
   std::cout << optcstr;
   for (pos=coll.begin(); pos!=coll.end(); ++pos) {
       std::cout << *pos << " ";
   }
   std::cout << std::endl;

} /* INSERT_ELEMENTS (collection, first, last)

* - fill values from first to last into the collection
* - NOTE: NO half-open range
*/

template <class T> inline void INSERT_ELEMENTS (T& coll, int first, int last) {

   for (int i=first; i<=last; ++i) {
       coll.insert(coll.end(),i);
   }

} using namespace std; int main() {

   vector<int> coll;
   INSERT_ELEMENTS(coll,1,9);
   PRINT_ELEMENTS(coll,"coll:      ");
   // rotate two elements to the right
   rotate (coll.begin(),      // beginning of range
           coll.end() - 2,    // new first element
           coll.end());       // end of range
   PRINT_ELEMENTS(coll,"two right: ");

}

/* 

coll: 1 2 3 4 5 6 7 8 9 two right: 8 9 1 2 3 4 5 6 7

*/       
 </source>

Use the generic rotate algorithm

<source lang="cpp">

1. include <iostream>
2. include <cassert>
3. include <algorithm>
4. include <vector>
5. include <string>

using namespace std; int main() {

 string s("Software Engineering ");
 vector<char> vector1(s.begin(), s.end());
 // Rotate the vector so that "Engineering " comes first:
 rotate(vector1.begin(), vector1.begin() + 9,vector1.end());

 for(int i=0;i<vector1.size();i++){
    cout << vector1[i] ;
 }
 return 0;

} /* Engineering Software

*/        
 </source>