Thread: Is it possible to 'reverse' a singly linked list?

As the title says, I have a singly linked list which has stored all the elements in backwards, would I have to create a new List and restore the data into that from the original list?

No. Just reverse the list. ( not the data, but the pointers)

How?

Sorry I'm a bit weak when it comes to Lists.

Originally Posted by hk_mp5kpdw

Or you can fix the problem at the source and not store the data in reverse order. Your insert function is storing items by creating a new node and setting the new node's next pointer to the start of the existing node. This results in a backwards list. What you want to do is set the last node's next pointer of the existing list to be equal to the new node you've just created (remember to set the new node's next pointer to NULL).
.

Ok I opted for this approach but am getting confused. Is it possible you can help me implement it in this code:

Code:

List *insertlist(char word, List * b)        
{
  List *c = calloc(1, sizeof(List));
  c->x = word; 
 c->next = b;
  return c;
}

Pop the old list and push it onto a new list.

No it can't be done. Is the short answer, that why doubley linked lists
are used.
The sensible thing to do would be to create a double linkedl ist in the
first place, rather than stand on you head and jump through hoops to
achieve the same thing.

Can somebody help me just store the data in the correct order instead of messing around with it later on?

Also another question, how do I access the end of the List, ie the tail?

Also another question, how do I access the end of the List, ie the tail?

u can have a tail pointer which points to the end of the list or u have to traverse all the way from the head to the end of the list thats is

Code:

struct .... *temp;

temp = head;

while(temp->link != NULL)
temp = temp->link;

ssharish2005

Originally Posted by Rash

This is not true; reversing a singly-linked list is simple to do.

Code:

node * reverse_in_place(node *list) {
    node *tail = NULL;
    node *tmp;
    while (list) {
        tmp = list->next;
        list->next = tail;
        list = tmp;
    }
    return tail;
}

If you only know the data from one element in the list
you can never go back up the list to the start.
If you wanted to go backwards you should make it a double
linked list.

How do you create a pointer to the tail?

eh??