Write a void function that takes a linked list of integers and reverses the order of its nodes.
--- The function will have one call-by-reference parameter that is a pointer to
the head of the list.
--- After the function is called, this pointer will point to the head
of a linked list that has the same nodes as the original list but in the reverse of the
order they had in the original list.
--- Note that your function will neither create nor destroy any nodes. It will simply rearrange nodes.