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 • ForwardIterator is a model of Forward Iterator.
• ForwardIterator is mutable.
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
', alpha);
// The output is nopqrstuvwxyzabcdefghijklm
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 Forward Iterators, Bidirectional Iterators, or Random Access Iterators. All three algorithms, however, are linear.
See also rotate_copy
Category: algorithms
Component type: function
Prototype template <class ForwardIterator, class OutputIterator>
OutputIterator rotate_copy(ForwardIterator first, ForwardIterator middle, ForwardIterator last, OutputIterator result);
Description Rotate_copy copies elements from the range [first, last) to the range [result, result + (last – first)) such that *middle is copied to *result, *(middle + 1) is copied to *(result + 1), and so on. Formally, for every integer n such that 0 <= n < last – first, rotate_copy performs the assignment *(result + (n + (last – middle)) % (last – first)) = *(first + n). Rotate_copy is similar to copy followed by rotate, but is more efficient. The return value is result + (last – first).
Definition Defined in the standard header algorithm, and in the nonstandard backward-compatibility header algo.h.
Requirements on types • ForwardIterator is a model of Forward Iterator.
• OutputIterator is a model of Output Iterator.
• ForwardIterator's value type is convertible to a type in OutputIterator's set of value types.
Preconditions • [first, middle) is a valid range.
• [middle, last) is a valid range. [1]
• There is enough space to hold all of the elements being copied. More formally, the requirement is that [result, result + (last – first)) is a valid range.
• The ranges [first, last) and [result, result + (last – first)) do not overlap.
Complexity Linear. Rotate_copy performs exactly last – first assignments.
Example const char alpha[] = 'abcdefghijklmnopqrstuvwxyz';
rotate_copy(alpha, alpha + 13, alpha + 26, ostream_iterator<char>(cout));
// The output is nopqrstuvwxyzabcdefghijklm
Notes [1] It follows from these two requirements that [first, last) is a valid range.
See also rotate, copy.
Category: algorithms
Component type: function
Prototype Random_shuffle is an overloaded name; there are actually two random_shuffle functions.
template <class RandomAccessIterator>
void random_shuffle(RandomAccessIterator first, RandomAccessIterator last);
template <class RandomAccessIterator, class RandomNumberGenerator>
void random_shuffle(RandomAccessIterator first, RandomAccessIterator last, RandomNumberGenerator& rand)
Description Random_shuffle randomly rearranges the elements in the range [first, last): that is, it randomly picks one of the N! possible orderings, where N is last – first. [1] There are two different versions of random_shuffle. The first version uses an internal random number generator, and the second uses a Random Number Generator, a special kind of function object , that is explicitly passed as an argument.
