Compare cnd copye the Linked List

int compare_linked_lists(struct node *q, struct node *r)

{

      static int flag;

      if((q==NULL ) && (r==NULL))

      {

           flag=1;

       }

      else

       {

           if(q==NULL || r==NULL)

            {

                flag=0;

             }

           if(q->data!=r->data)

             {

                  flag=0;

              }

            else

              {

                  compare_linked_lists(q->link,r->link);

               }

    }

    return(flag);

}

copy_linked_lists(struct node *q, struct node **s)

{

      if(q!=NULL)

      {

          *s=malloc(sizeof(struct node));

         (*s)->data=q->data;

         (*s)->link=NULL;

         copy_linked_list(q->link, &((*s)->link));

       }

}