We have already discussed about circular linked list and traversal in a circular linked list in the below articles:

Introduction to circular linked list

Traversal in a circular linked list

In this article we will learn about deleting a node from a cicular linked list. Consider the linked list as shown below:

We will be given a node and our task is to delete that node from the circular linked list.

Examples:

Input : 2->5->7->8->10->(head node) data = 5 Output : 2->7->8->10->(head node) Input : 2->5->7->8->10->(head node) 7 Output : 2->5->8->10->2(head node)

**Algorithm**

**Case 1**: List is empty.

- If the list is empty we will simply return.

**Case 2**:List is not empty

- If the list is not empty then we define two pointers
**curr**and**prev**and initialize the pointer**curr**with the**head**node. - Traverse the list using
**curr**to find the node to be deleted and before moving curr to next node, everytime set prev = curr. - If the node is found, check if it is the only node in the list. If yes, set head = NULL and free(curr).
- If the list has more than one node, check if it is the first node of the list. Condition to check this( curr == head). If yes, then move prev until it reaches the last node. After prev reaches the last node, set head = head -> next and prev -> next = head. Delete curr.
- If curr is not first node, we check if it is the last node in the list. Condition to check this is (curr -> next == head).
- If curr is the last node. Set prev -> next = head and delete the node curr by free(curr).
- If the node to be deleted is neither the first node nor the last node, then set prev -> next = temp -> next and delete curr.

**Complete C program to demonstrate deletion in Circular Linked List:**

// C program to delete a given key from // 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 ptr1->next = ptr1; /*For the first node */ *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 (head == NULL) return; // Find the required node struct Node *curr = head, *prev; while (curr->data != key) { if (curr->next == head) { printf("\nGiven node is not found" " in the list!!!"); break; } prev = curr; curr = curr -> next; } // Check if node is only node if (curr->next == head) { head = NULL; free(curr); return; } // If more than one node, check if // it is first node if (curr == head) { prev = head; while (prev -> next != head) prev = prev -> next; head = curr->next; prev->next = head; free(curr); } // check if node is last node else if (curr -> next == head) { prev->next = head; free(curr); } else { prev->next = curr->next; free(curr); } } /* Driver program to test above functions */ 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; }

**Output**:

List Before Deletion: 10 8 7 5 2 List After Deletion: 10 8 5 2

This article is contributed by **Harsh Agarwal**. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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