STL: rotate

rotate

Exchanges the elements in two adjacent ranges.

template<class ForwardIterator> 
   void rotate( 
      ForwardIterator _First,  
      ForwardIterator _Middle,  
      ForwardIterator _Last 
   );

rotate_copy

Exchanges the elements in two adjacent ranges within a source range and copies the result to a destination range.

template<class ForwardIterator, class OutputIterator> 
   OutputIterator rotate_copy( 
      ForwardIterator _First,  
      ForwardIterator _Middle, 
      ForwardIterator _Last,  
      OutputIterator _Result 
   );

rotate和swap_ranges()功能颇为近似，但是swap_ranges只能交换两个长度相同的区间，rotate却可以交换两个长度不同的区间。所以如果两个区间的长度相同，则优先使用swap_ranges；而区间长度不同时，则使用rotate。