How do display the list in single linked list form last to first

Gyan Prakash

Aug 10th, 2006

display(node *p){ if(p->next==NULL) printf("%d ",p->info); else { display(p->next); printf("%d ",p->info); }}

Nilanjan Mukhopadhyay

Aug 14th, 2006

void reverse_list(Node**hp)
{
Node*p,*q,*r;
if(*hp==NULL || (*hp)->next==NULL)
   {
    printf("nReversing is not possible...");
    getch();
    return;
   }
   r=NULL;q=*hp;p=q->next;
   while(p!=NULL)
   {
    q->next=r;
    r=q;
    q=p;
    p=p->next;
   }
   q->next=r;
   *hp=q;
}
//hp=head pointer
p,q,r are the nodes of a linklist
should be called from the main as
reverse_list(&head);
head= head pointer in main func

Avinash

Sep 8th, 2006

typedef struct _node
{
char *data;
struct _node *next;
} node ;
node *head=NULL;
main()
{
LinkedList();
}

void LinkedList()
{
AddNode("hello");
AddNode("how");
AddNode("are");
AddNode("you");
AddNode("?");
PrintList();
ReverseList();
PrintList();
}
void ReverseList()
{
node *prev, *curr, *next;
prev=NULL;
curr=head;
next=head->next;
while( NULL != curr )
{
  curr->next=prev;
  prev=curr;
  curr=next;
  if ( curr != NULL ) next=curr->next;
}
head=prev;
}

void PrintList()
{
node *temp;
/* Traverse*/
temp=head;
while ( NULL != temp )
{
  printf("[%s]->",temp->data);
  temp=temp->next;
}
printf("NULLn");
}
int AddNode(char *data)
{
node * temp=NULL;
/* If first node */
if ( NULL == head )
{
  if ( NULL == (head = (node *) malloc(sizeof(struct _node))) )
  {
   printf("error allocating memory for new node n");
   return 1;
  }

  if ( NULL == (head->data = (char *) malloc(sizeof(data))))
  {
   printf("error allocating memory for node datan");
   return 1;
  }
  strcpy(head->data,data);
  head->next=NULL;
  return 0;
}
/* Goto last node */
temp=head;
while ( NULL != temp->next )
{
  temp=temp->next;
}
/* Allocate memory for last node */
if ( NULL == (temp->next = (node *) malloc(sizeof(struct _node))) )
{
  printf("error allocating memory for new node n");
  return 1;
}

if ( NULL == (temp->next->data = (char *) calloc(DATA_SIZE,sizeof(char))) )
{
  printf("error allocating memory for node datan");
  return 1;
}
strcpy(temp->next->data,data);
temp->next->next=NULL;
return 0;
}