circular_linkedlist.c

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
struct node
{
    int data;
    struct node *next;
}*head=NULL;
void create(int a[],int n)
{
    int i=0,j=0;
    struct node *t,*last;
    head=(struct node*)malloc(sizeof(struct node));
    head->data=a[0];
    head->next=head;
    last=head;
    for(i=1;i<n;i++)
    {
        t=(struct node*)malloc(sizeof(struct node));
        t->data=a[i];
        t->next=last->next;
        last->next=t;
        last=t;
    }
}
void display()
{
    struct node *p=head;
    do
    {
        printf("%d ",p->data);
        p=p->next;
    } while (p!=head);
    
}
void insert(int position,int x)
{
    int i,j;
    struct node *p;
    struct node *t=head;
    
    if(position==1)
    {
        p=(struct node*)malloc(sizeof(struct node));
        p->data=x;
          if(head==NULL)
          {
            head=p;
            head->next=head;
          }
          else
          {
            while(t->next!=head)
           { t=t->next;}
            t->next=p;
            p->next=head;
            head=p;
          }
    }
    else
    {
        p=(struct node*)malloc(sizeof(struct node));
        p->data=x;
        for(i=1;i<position-1;i++)
        {t=t->next;}
        p->next=t->next;
        t->next=p;


    }
}
int delete(int position)
{
   struct node *p=head;
   struct node *q;int x;
   if(position==1)
   {
       x=head->data;
       while(p->next!=head)
       {
           p=p->next;
       }
       p->next=head->next;
       free(head);
       head=p->next;
       return x;
   }
   else 
   {
       for(int i=0;i<position-2;i++)
       {
           p=p->next;
       }
       q=p->next;
       x=q->data;
       p->next=q->next;
       free(q);
       return x;
   }
}
void main()
{
   int a[]={2,3,4,5,6,7};
   create(a,6);
   display();
   insert(3,9);
   display();
   printf("%d",delete(4));
}