Write a Program to Circular Linked lists

Program

# include <stdlib.h>

struct node
{
   int data;
   struct node *link;
};
struct node *insert(struct node *p, int n)
{
   struct node *temp;
   /* if the existing list is empty then insert a new node as the
starting node */
       if(p==NULL)
       {
         p=(struct node *)malloc(sizeof(struct node)); /* creates new
node data value passes
   as parameter */
        if(p==NULL)
        {
                 printf("Error\n");
                 exit(0);
         }
         p-> data = n;
          p-> link = p; /* makes the pointer pointing to itself because it
is a circular list*/
      }
      else
      {
         temp = p;
   /* traverses the existing list to get the pointer to the last node of
it */
         while (temp-> link != p)
                temp = temp-> link;
         temp-> link = (struct node *)malloc(sizeof(struct node)); /*
creates new node using
         data value passes as
         parameter and puts its
         address in the link field
         of last node of the
         existing list*/
         if(temp -> link == NULL)
         {
                  printf("Error\n");
         }
            exit(0);
            temp = temp-> link;
            temp-> data = n;
            temp-> link = p;
         }
         return (p);
   }
   void printlist ( struct node *p )
   {
      struct node *temp;
      temp = p;
      printf("The data values in the list are\n");
      if(p!= NULL)
      {
      do
      {
                printf(%d\t",temp->data);
                temp=temp->link;
      } while (temp!= p)
   }
   else
      printf("The list is empty\n");
   }

   void main()
   {
      int n;
      int x;
      struct node *start = NULL ;
      printf("Enter the nodes to be created \n");
      scanf("%d",&n);
      while ( n- > 0 )
      {
              printf( "Enter the data values to be placed in a
node\n");
         scanf("%d",&x);
         start = insert ( start, x );
      }
      printf("The created list is\n");
      printlist ( start );
   }

Explanation

The program appends a new node to the existing list (that is, it inserts a new node in the existing list at the end), and it makes the link field of the newly inserted node point to the start or first node of the list. This ensures that the link field of the last node always points to the starting node of the list