Circular Linked List in C

#include<stdio.h>
#include<stdlib.h>
// structure for Circular Linked List
struct Node
{
   int data;
   struct Node *next;
};

void insertLast(struct Node** head, int data){
    struct Node* newNode = (struct Node*) malloc(sizeof(struct Node));
    newNode->data = data;
    
    // if its the first node being entered
    if(*head == NULL){
        *head = newNode;
        (*head)->next = *head;
        return;
    }
    
    // if LL already as >=1 node
    struct Node* curr = *head;
    
    // traverse till last node in LL
    while(curr->next != *head){
        curr = curr->next;
    }
    
    // assign LL's current last node's next as this new node
    curr->next = newNode;
    
    // assign this new node's next as current head of LL
    newNode->next = *head;
}

void insertStart(struct Node** head, int data){
    struct Node* newNode = (struct Node*) malloc(sizeof(struct Node));
    newNode->data = data;
    
    // if its the first node being entered
    if(*head == NULL){
        *head = newNode;
        (*head)->next = *head;
        return;
    }
    
    // if LL already as >=1 node
    struct Node* curr = *head;
    
    // traverse till last node in LL
    while(curr->next != *head){
        curr = curr->next;
    }
    curr->next = newNode;
    newNode->next = *head;
    *head = newNode;
}

void display(struct Node* head){
    // if there are no node in LL
    if(head == NULL)
        return;
    
    struct Node* temp = head;
    
    //need to take care of circular structure of LL
    do{
        printf("%d ", temp->data);
        temp = temp->next;
        
    }while(temp!=head);
    printf("\n");
}

int main(){
    
    // first node will be null at creation    
    struct Node* head = NULL;
    
    insertStart(&head,2);
    insertStart(&head,1);

    display(head);
    
    insertLast(&head, 30);
    insertLast(&head, 40);
    
    display(head);
    
    return 0;
}