Standard C++ Library Class Reference

Description
The rotate algorithm takes three iterator arguments, first, which defines the start of a sequence,
last, which defines the end of the sequence, and middle which defines a point within the
sequence. rotate "swaps" the segment that contains elements from first through middle-1 with
the segment that contains the elements from middle through last. After rotate has been applied,
the element that was in position middle, is in position first, and the other elements in that
segment are in the same order relative to each other. Similarly, the element that was in position
first is now in position last-middle +1. An example will illustrate how rotate works:
Say that we have the sequence:
2 4 6 8 1 3 5
If we call rotate with middle = 5, the two segments are
2 4 6 8 and 1 3 5
After we apply rotate, the new sequence will be:
1 3 5 2 4 6 8
Note that the element that was in the fifth position is now in the first position, and the element
that was in the first position is in position 4 (last - first + 1, or 8 - 5 +1 =4).
The formal description of this algorithms is: for each non-negative integer i < (last - first), rotate
places the element from the position first + i into position first + (i + (last - middle)) % (last -
first). [first, middle) and [middle, last) are valid ranges.
rotate_copy rotates the elements as described above, but instead of swapping elements within the
same sequence, it copies the result of the rotation to a container specified by result. rotate_copy
copies the range [first, last) to the range [result, result + (last - first)) such that for each non-
negative integer i < (last - first) the following assignment takes place:
*(result + (i + (last - middle)) % (last -first)) = *(first + i).
The ranges [first, last) and [result, result, + (last - first)) may not overlap.
Complexity
For rotate at most last - first swaps are performed.
For rotate_copy last - first assignments are performed.
Example
//
// rotate
//
#include <algorithm>
#include <vector>