Circular Linked list Implementation code is given below:

//Code for Implementation of Circular Linked List
#include <stdio.h>
#include <stdlib.h>
struct node
{
    int data;
    struct node *link;

} *head = NULL;
struct node* tail;
int length()
{
    int length = 0;
    struct node *t;
    t=head;
    while(t->link != head)
    {
        length++;
        t = t ->link;
    }
    length++;
    return length;
}
void insertbegin(int item)
{
    struct node *newnode;
    newnode = (struct node *)malloc(sizeof(struct node));
    newnode->data = item;
    newnode->link = newnode;
    if (head == NULL)
    {
        head= tail = newnode;
    }
    else
    {
        newnode->link = head;
        head = newnode;
        tail->link=head;
    }
}
void insertend(int item)
{
    struct node *newnode, *t;
    newnode = (struct node *)malloc(sizeof(struct node));
    newnode->data = item;
    newnode->link = newnode;
    t = head;
    if (head == NULL)
    {
        head = tail= newnode;
    }
    else
    {
        tail->link=newnode;
        newnode->link=head;
        tail=newnode;
    }
}
void insertpos(int item, int pos)
{
    struct node *newnode, *t;
    int i;
    newnode = (struct node *)malloc(sizeof(struct node));
    newnode->data = item;
    newnode->link = newnode;
    t = head;
    int l=length();
    if (pos>l+1)
    {
        printf("\nInvalid position");
    }
    else if(pos == 1)
    {
       insertbegin(item);
    }
    else if(pos == l+1)
    {
       insertend(item);
    }
    else{
        for(int i=1;i<pos-1;i++)
        {
            t=t->link;
        }
        newnode->link=t->link;
        t->link=newnode;
    }
}
void deletefront()
{
    struct node *t;
    if (head == NULL)
    {
        printf("empty");
    }
    else if(head->link==head)
    {
        printf("\ndeleted data is %d ", head->data);
        head = tail = NULL;
    }
    else
    {
        t = head;
        printf("\ndeleted data is %d ", t->data);
        head = head->link;
        tail->link=head;
        free(t);
    }
}
void deleteend()
{
    struct node *t1, *t2;
    t2 = head;
    if (head == NULL)
    {
        printf(" list is empty");
    }
    else if(head->link==head)
    {
        printf("\ndeleted data is %d ", head->data);
        head = tail = NULL;
    }
    else
    {
        while (t2->link != tail->link)
        {
           t1=t2;
           t2=t2->link;
        }
        if(t2==head)
           {
            head = NULL;
           }
        else{
            t1->link=t2->link;
            tail=t1;
           }
        printf("\n deleted element is %d ", t2->data);
        free(t2);
    }
}

void deletepos(int pos)
{
    int l=length();
    struct node *t1, *t2;
    t2 = head;
    if (head == NULL)
    {
        printf("empty");
    }
    else
    {
        if(pos > l)
        {
            printf("Invalid position");
        }
        else if(pos == 1)
        {
            deletefront();
        }
        else if(pos == l)
        {
            deleteend();
        }
        else{
        for(int i =1;i<pos;i++)
        {
           t1=t2;
           t2=t2->link;
        }
        t1->link=t2->link;
        printf("\ndeleted element is %d ", t2->data);
        free(t2);
        }
    }
}
void display()
{
    struct node *t = head;
    if(head == NULL)
    {
        printf("LIst is empty");
    }
    else{
    while (t->link != head)
    {
        printf("_%d_", t->data);
        t = t->link;
    }
    printf("_%d_", t->data);
    }
}

void main()
{
   int choice ,c,data,x;
    do{
    printf("press 1 to insert in begning\n");
    printf("press 2 to insert in end\n");
    printf("press 3 to insert in any positions\n");
    printf("press 4 to delete first element\n");
    printf("press 5 to delete end element\n");
    printf("press 6 to to delete in any position\n");
    printf("press 7 to display\n");
    printf("press 8 for the length of current list\n");
     printf("press 0 to Exit\n");
    fflush(stdin);
    scanf(" %d",&choice);
    switch(choice)
    {
        case 1 :
        printf(" Enter the data to insert :");
        scanf(" %d",&data);
        insertbegin(data);

        break;
        case 2 :
         printf(" Enter the data to insert :");
        scanf(" %d",&data);
        insertend(data);

        break;
        case 3 :
         printf(" Enter the data to insert :");
        scanf(" %d",&data);
         printf(" Enter the position to insert :");
        scanf(" %d",&x);
        insertpos(data,x);

        break;
        case 4 :
        deletefront();
        break;
        case 5 :
        deleteend();
        break;
        case 6 :
         printf(" Enter the position to delete :");
        scanf(" %d",&x);
        deletepos(x);
        break;
        case 7 :
        display();
        break;
        case 8 :
        printf("\n the length of current list :%d",length());
        break;
        case 0: 
        exit(1);
        break;
        default:
        printf("\nEnter the correct value");

    }
    printf("\nEnter 1 to continue :");
    fflush(stdin);
    scanf(" %d",&c);
    }while(c==1);
}

Output

press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
1
 Enter the data to insert :55

Enter 1 to continue :1
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
7
_55__22__11__33__66_
Enter 1 to continue :1
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
5

 deleted element is 66
Enter 1 to continue :1
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
7
_55__22__11__33_
Enter 1 to continue :1
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
6
 Enter the position to delete :2

deleted element is 22
Enter 1 to continue :1
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
7
_55__11__33_
Enter 1 to continue :1
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
8

 the length of current list :3
Enter 1 to continue :1
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
0