1.90LinkedLists_Circular

//       CIRCULAR LINKED LISTS
#include<stdio.h>
#include<conio.h>
#include<malloc.h>
struct node
{
 int data;
 struct node *link;
};
void append(struct node **,struct node **,int );
void Delete(struct node **,struct node **);
void main()
{
  clrscr();
  struct node *n,*m,*o,*p;
  n=NULL; m=NULL;
  append(&n,&m,12);
  append(&n,&m,67);
  append(&n,&m,45);
  append(&n,&m,34);
  append(&n,&m,32);
  p=n;      o=NULL;
  printf("Appending: ");
  while(n!=o)
  {
   printf("%d ",(n->data));
   n=n->link;
   o=p;
  }
  o=NULL;
  n=p;
  Delete(&n,&m);
  p=n;
  printf("\nAfter Deleting: ");
  while(n!=o)
  {
   printf("%d ",(n->data));
   n=n->link;
   o=p;
  }
  free(n); free(m);
  getch();
}
/*any element we want to insert to circular linked lists will get inserted on rear */
void append(struct node **a,struct node **b,int num)
{
 struct node *temp;
 temp=(struct node *)malloc(sizeof(struct node));
 temp->data=num;
 if(*a==NULL)
 {
  *a=temp;
 }
 else
 {
  (*b)->link=temp;
 }
 *b=temp;
 (*b)->link=*a;
}
/*any element we want to delete in a circular linked list will get deleted from front */
void Delete(struct node **a,struct node **b)
{
 struct node *temp;
 if(*a==NULL)
 {
  printf("empty list");
 }
 else
 {
   if(*a==*b)
   {
    *a=NULL;
    *b=NULL; 
   }
   else
   {
    (*a)=(*a)->link;
    (*b)->link=(*a);
   }  
 }
}