Circular linked list code with output

Code

#include<stdio.h>
#include<stdlib.h>

typedef struct node
{
        int id;
        struct node* next;            //for storing address of next node
}node;

node* create();
node* append(node*);
node* modify(node*);
node* del(node*);
void display(node*);

node* create()
{
    node* head;
    head=(node*)malloc(sizeof(node));  /*allocating memory to node 
                                       and head is pointing to it  */

    printf("\nEnter employee id ");
    scanf("%d",&head->id);

    head->next=head;
    return head;
}   


node* append(node* head)
{
    node* curr = (node*)malloc(sizeof(node));  //allocate memory for current node

    node* prev = head;

    printf("\nEnter employee id ");
    scanf("%d",&curr->id);

    while(prev->next!=head)                    //traverse the list and go to the last node
        prev = prev->next;

    prev->next = curr;                          /*establish the link between last node(pointed by
                                                prev) and curr node   */

    curr->next = head;

    return head;
}

node* modify(node* head)
{
    node* curr=head;
    int eid,found=0;

    printf("\nEnter Eid of employee whose data is to be modified ");
    scanf("%d",&eid);

    do                                         //traverse list in search of eid
    {
           if(curr->id==eid)
           {
              found = 1;
              break;
           }
           else
              curr=curr->next;
    }while(curr!=head);

    if(found == 1)                            //eid is found
    {
            printf("\nEnter employee id ");
            scanf("%d",&curr->id);
    }
    else
            printf("\nEmployee id not found");

    return head;
}

node* del(node* head)
{
    node *prev,*curr=head,*last;
    int eid;

    printf("\nEnter employee id to be deleted ");
    scanf("%d",&eid);

    if(curr==NULL)
           return NULL;

    else if(curr->id==eid && curr->next==curr)          //only 1 node
    {
           free(curr);
           return NULL;
    }

    else if(curr->id==eid && curr->next!=head)          //1st node
    {
           head=head->next;

           last = head;                                //go to last node
           do                                               
           {
                 last=last->next;
           }while(last->next!=curr);

           last->next=head;

           free(curr);
           return head;
    }


    else
    {
           do                                          //search node
           {
               if(curr->id==eid)
               break;
               else
               {
                    prev=curr;
                    curr=curr->next;
               } 
            }while(curr!=head);

            if(curr!=head)                             //if eid found
            {
                   //establish the link between prev & node ahead of curr
                   prev->next=curr->next;

                   free(curr);
            }
            else
                   printf("\nEmployee id not found");

            return head;
       }
}

void display(node* head)
{
    node* curr=head;

    if(curr==NULL)
           printf("\nList is empty");
    else
    {
            printf("\n");

            do
            {
                 printf("%d---",curr->id);
                 curr=curr->next;
            }while(curr!=head);

    }
}

int main()
{
    node* head = NULL;
    int ch;

    do
    {
        printf("\n1.Create   2.Append   3.Modify   4.Delete   5.Display\nEnter choice ");
        scanf("%d",&ch);

        switch(ch)
        {
            case 1:
                head = create();
                break;
            case 2:
                head = append(head);
                break;

            case 3:
                head = modify(head);
                break;


            case 4:
                head = del(head);
                break;

            case 5:
                display(head);
                break;

        }

        printf("\nContinue? ");
        fflush(stdin);

    }while(getchar()=='y');

    return 0;    
}

O/P