Circular Linked List

#include <stdio.h>
#include <stdlib.h>
// Structure for a node
struct Node {
int data;
struct Node* next;
};
// Function to insert a node at the
// beginning of a Circular linked list
void push(struct Node** head_ref, int data)
{
// Create a new node and make head
// as next of it. 
struct Node* ptr1 = (struct Node*)malloc(sizeof(struct Node));
ptr1->data = data;
ptr1->next = *head_ref;
// If linked list is not NULL then
// set the next of last node
if (*head_ref != NULL) {
// Find the node before head and
// update next of it. 
struct Node* temp = *head_ref;
while (temp->next != *head_ref)
temp = temp->next;
temp->next = ptr1;
}
else
// For the first node
ptr1->next = ptr1; *head_ref = ptr1;
}
// Function to print nodes in a given
// circular linked list
void printList(struct Node* head)
{
struct Node* temp = head;
if (head != NULL) {
do {
printf("%d ", temp->data);
temp = temp->next;
} while (temp != head);
}
printf("\n");
}
// Function to delete a given node
// from the list
void deleteNode(struct Node** head, int key)
{
// If linked list is empty
if (*head == NULL)
return;
// If the list contains only a
// single node
if ((*head)->data == key && (*head)->next == *head) {
free(*head); *head = NULL;
return;
}

struct Node *last = *head, *d;
// If head is to be deleted
if ((*head)->data == key) {
// Find the last node of the list
while (last->next != *head)
last = last->next;
// Point last node to the next of
// head i.e. the second node
// of the list
last->next = (*head)->next;
free(*head); *head = last->next;
return;
}
// Either the node to be deleted is
// not found or the end of list
// is not reached
while (last->next != *head && last->next->data != key) {
last = last->next;
}
// If node to be deleted was found
if (last->next->data == key) {
d = last->next;
last->next = d->next;
free(d);
}
else
printf("Given node is not found in the list!!!\n");
}
// Driver code
int main()
{
// Initialize lists as empty
struct Node* head = NULL;
// Created linked list will be
// 2->5->7->8->10
push(&head, 2);
push(&head, 5);
push(&head, 7);
push(&head, 8);
push(&head, 10);
printf("List Before Deletion: ");
printList(head);
deleteNode(&head, 7);
printf("List After Deletion: ");
printList(head);
return 0;
}