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| Category: algorithms | | Component type: function |
Prototype
template <class ForwardIterator>
inline ForwardIterator rotate(ForwardIterator first, ForwardIterator middle,
ForwardIterator last);
Description
Rotate rotates the elements in a range. That is, the element pointed to by middle is moved to the position first, the element pointed to by middle + 1 is moved to the position first + 1, and so on. One way to think about this operation is that it exchanges the two ranges [first, middle) and [middle, last). Formally, for every integer n such that 0 <= n < last - first, the element *(first + n) is assigned to *(first + (n + (last - middle)) % (last - first)). Rotate returns first + (last - middle).
Definition
Defined in the standard header algorithm, and in the nonstandard backward-compatibility header algo.h.
Requirements on types
Preconditions
-
[first, middle) is a valid range.
-
[middle, last) is a valid range. [1]
Complexity
Linear. At most last - first swaps are performed. [2]
Example
char alpha[] = "abcdefghijklmnopqrstuvwxyz";
rotate(alpha, alpha + 13, alpha + 26);
printf("%s\n", alpha);
Notes
[1] It follows from these two requirements that [first, last) is a valid range.
[2] Rotate uses a different algorithm depending on whether its arguments are ForwardIterator, BidirectionalIterator, or RandomAccessIterator. All three algorithms, however, are linear.
See also
rotate_copy
