Reverse a Linked List - Recursive Solution

Function to reverse a linked list - recursive solution

void reverse(struct node *pred, struct node *curr)
{
  if(curr)
  {
    reverse(curr, curr -> link);
    curr -> link = pred;
  }
  else
    first = pred;
}

void main()
{
  reverse(NULL, first);
}

Written by Munia Balayil

Reverse a Linked List - Iterative Solution

Function to reverse a linked list - iterative solution

void reverse(struct node *first)
{
  // p is used to traverse the linked list
  struct node *p = first;
  // q points to the start of the reversed list
  struct node *q = NULL;
  // r is a temporary variable used in this process
  struct node *r;

  while(p)
  {
    r = q;
    q = p;
    p = p -> link;
    q -> link = r;
  }
  first = q;
}

Written by Munia Balayil

Count the Number of Nodes in a Linked List - Recursive Solution

Function to count the number of nodes in a linked list - recursive solution

int count(struct node *p)
// p is a pointer to the first node of the list.
{
  if(p)
    return 1 + count(p->link);
  else
    return 0;
}

Written by Munia Balayil

Function to count the number of nodes in a linked list - iterative solution

int count(struct node *first)
// first is a pointer to the first node
{
  struct node *p = first;
  int count = 0;
  while(p)
  {
    ++count;
    p = p->link;
  }
  // Final value of count gives the number of nodes
  // in the linked list.
  return count;
}

Written by Munia Balayil