#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
 typedef struct cllist{
    int x;
    struct cllist *next;
    }nd;
   nd*insert(nd**,nd**,nd**);
   nd*delete(nd**,nd**,nd**);
   nd*insfro(nd**,nd**,nd**);
   nd*insaftnd(nd**,nd**,nd**);
   void display(nd*,nd*);
   void main()
   {
    int n;
    nd *start,*current,*head;
    head=(nd*)malloc(sizeof(nd));
    start=head;
    current=start;
     do{
     clrscr();
     textbackground(RED);
     textcolor(BLACK+BLINK);
     printf("
				CIRCULAR LINKED
LIST
			_________________________________________
");
     printf("
					MAIN
MENU
				----------------------------
");
     printf("
		1>. INSERT

		2>.INSERTION AT
FRONT

		3>.INSERION AFTER A
NODE

		4>.DELETION

		5>.END
");

printf("
	______________________________________________________
");
     printf("
enter your choice: ");
     scanf("%d",&n);
     switch(n)
     {
      case 1:
	insert(&head,&start,¤t);
	break;
      case 2:
	insfro(&head,&start,¤t);
	break;
      case 3:
	 insaftnd(&head,&start,¤t);
	 break;
      case 4:
	   if(start==head){
	    printf("
the list empty!");
	    break;
	    }
	  delete(&head,&start,¤t);
	  break;
	case 5:
	 clrscr();
	 printf("








");
	 printf("			press any key to exit...");
	 getch();
	 exit(0);
	 default:
	  printf("
invalid choice!");
	  getch();
	  break;
	  }
	 }while(n!=5);
	 getch();
	 }
	nd*insert(nd**head,nd**start,nd**current)
	{
	 int m;
	 nd*temp,*val;

	  clrscr();

printf("
				INSERTION
			______________________________________
n");
	  do{
	 temp=(nd*)malloc(sizeof(nd));
	 if(!temp ){
	  printf("memory allocation not possible!");
	  getch();
	  exit(0);
	  }
	  val=temp;
	  temp=temp->next;
	  printf("
enter the element:");
	  scanf("%d",&m);
	  val->x=m;
	  val->next=*head;
	  if(*start==*head){
	   (*head)->next=val;
	   *start=val;
	   *current=*start;
	   }
	  else{
	   (*current)->next=val;
	   *current=val;
	   }
	   printf("
any more inserton(y/n):");
	   fflush(stdin);
	   }while(toupper(getch())!='N');
	   display(*head,*start);
	   getch();
	   return(*head,*start,*current);
	   }
	  void display(nd*head,nd*start)
	  {
	   if(head==start){
	    printf("
the list is empty!");
	    getch();
	    return;
	    }
	    else{
	     printf("
the list is now:
");
	     do{
	     printf("%5d",start->x);
	     start=start->next;
	     }while(start!=head);
	   }
	   return;
	   }
	nd*delete(nd**head,nd**start,nd**current)
	{
	 int ele;
	 nd *temp,*save,*val,*pred;

	 clrscr();

printf("
				DELETION

			___________________________________
"
);
	 save=*start;
	   do{
	  display(*head,*start );

	  	  val=save;
	  printf("
enter the element to be deleted:");
	  scanf("%d",&ele);
	  while(save->x!=ele && save->next!=val){
	   pred=save;
	   save=save->next;

	   }
	   if(save->next==val){
	    printf("
the elment is not in the list!");
	    getch();
	    break;
	    }
	   temp=save;
	   printf("
the element to be deleted is:%d",temp->x);
	   printf("
r u sure(y/n):");
	   fflush(stdin);
	   if(toupper(getch())!='N'){
	    if(save==(*head)->next){
	     *start=(*start)->next;
	     free(temp);
	     save=*start;
	     }
	     else if(save->next==*head){
	     pred->next=*head;
	     *current=pred;
	     free(temp);
	     save=pred;
	     }
	     else{
	      pred->next=temp->next;
	      free(temp);
	      save=pred;
	      }
	     }
	    else
	    break;
	    printf("
anymore deletion(y/n):");
	    fflush(stdin);
	    }while(toupper(getch())!='N');
	    display(*head,*start);
	    getch();
	    return(*head,*start,*current);
	    }

	    nd*insfro(nd**head,nd**start,nd**current)
	    {
	     int m;
	     nd *temp,*val;
	      clrscr();
	      printf("
			INSERTION IN FRONT
");
	      printf("
		__________________________________
");
	      do{
	       temp=(nd*)malloc(sizeof(nd));
	       if(!temp){
		printf("
memory allocation not possible!");
		getch();
		exit(0);
		}
		val=temp;
		temp=temp->next;
		printf("
enter the element:");
	       scanf("%d",&m);
	       val->x=m;
	       if(*start==*head){
	       val->next=*head;
		(*head)->next=val;
		*start=val;
		*current=*start;
		}
		else{
		 (*head)->next=val;
		 val->next=*start;
		 *start=val;
		 }
		printf("
any more insertion to be performed(y/n):");
		fflush(stdin);
		}while(toupper(getch())!='N');
		display(*head,*start);
		getch();
		return(*head,*start,*current);
		}

	   nd*insaftnd(nd**head,nd**start,nd**current)
	   {
	    int trg,n=1,m;
	    nd *temp,*val,*save,*pred;
	    save=*start;
	    clrscr();
	    printf("
			INSERTION AFTER A NODE
");
	    printf("
		__________________________________
");
	    do{
	    display(*head,*start);
	     temp=(nd*)malloc(sizeof(nd));
	     if(!temp){
	      printf("
memory allocation not possible!");
	      getch();
	      exit(0);
	      }
	      val=temp;
	      temp=temp->next;
	      printf("
enter the element:");
	      scanf("%d",&m);
	      val->x=m;
	      if(*start==*head){
	       val->next=*head;
	       (*head)->next=val;
	       *start=val;
	       *current=*start;
	       }
	       else{
		printf("
enter the position of insertion:");
		scanf("%d",&trg);
		while(trg!=n){
		 pred=save;
		 save=save->next;
		 n++;
		 if(save==*head)
		 n=0;
		 }
		 pred->next=val;
		 val->next=save;
		 save=save->next;
		 }
		 printf("
any more insertion(y/n):");
		 fflush(stdin);
		}while(toupper(getch())!='N');
		display(*head,*start);
		getch();
		return(*head,*start,*current);
		}