What is the purpose of the reverse function in C++?

The reverse function in C++ is used to reverse the elements in a container. It swaps the first element with the last element, the second element with the second to last element, and so on, until all elements in the container are reversed.

For example, when the reverse function is applied to an integer array {1, 2, 3, 4, 5}, the contents of the array will be changed to {5, 4, 3, 2, 1}.

The definition of the reverse function is as follows:

template <class BidirectionalIterator>
  void reverse (BidirectionalIterator first, BidirectionalIterator last);

BidirectionalIterator is a type of iterator used to point to elements in the container. ‘First’ is the iterator pointing to the starting position of the range to be reversed, while ‘last’ is the iterator pointing to the element after the end position of the range to be reversed.

It is important to note that the reverse function can only be used with containers that support bidirectional iterators, such as vector, list, and deque. Containers that only support forward iterators, like forward_list, cannot use the reverse function.