Reverse a Doubly Linked List

/* Program to reverse a doubly linked list */
#include <stdio.h>
#include <stdlib.h>
 
/* a node of the doubly linked list */
struct node
{
  int data;
  struct node *next;
  struct node *prev;    
};
 
/* Function to reverse a Doubly Linked List */
void reverse(struct node **head_ref)
{
     struct node *temp = NULL;  
     struct node *current = *head_ref;
      
     /* swap next and prev for all nodes of 
       doubly linked list */
     while (current !=  NULL)
     {
       temp = current->prev;
       current->prev = current->next;
       current->next = temp;              
       current = current->prev;
     }      
      
     /* Before changing head, check for the cases like empty 
        list and list with only one node */
     if(temp != NULL )
        *head_ref = temp->prev;
}     
 
 
 
/* UTILITY FUNCTIONS */
/* Function to insert a node at the beginging of the Doubly Linked List */
void push(struct node** head_ref, int new_data)
{
    /* allocate node */
    struct node* new_node =
            (struct node*) malloc(sizeof(struct node));
  
    /* put in the data  */
    new_node->data  = new_data;
     
    /* since we are adding at the begining, 
      prev is always NULL */
    new_node->prev = NULL;
  
    /* link the old list off the new node */
    new_node->next = (*head_ref);    
 
    /* change prev of head node to new node */
    if((*head_ref) !=  NULL)
      (*head_ref)->prev = new_node ;    
  
    /* move the head to point to the new node */
    (*head_ref)    = new_node;
}
 
/* Function to print nodes in a given doubly linked list 
   This function is same as printList() of singly linked lsit */
void printList(struct node *node)
{
  while(node!=NULL)
  {
   printf("%d ", node->data);
   node = node->next;
  }
} 
 
/* Drier program to test above functions*/
int main()
{
  /* Start with the empty list */
  struct node* head = NULL;
  
  /* Let us create a sorted linked list to test the functions
   Created linked list will be 10->8->4->2 */
  push(&head, 2);
  push(&head, 4);
  push(&head, 8);
  push(&head, 10);
  
  printf("\n Original Linked list ");
  printList(head);
  
  /* Reverse doubly linked list */
  reverse(&head);
  
  printf("\n Reversed Linked list ");
  printList(head);           
  
  getchar();
}