#include using namespace std; /* defines the structure of a single linked list node*/ typedef struct list_node { int data; struct list_node *next; // pointer to next node in the list }node; /* create new node */ node *getNewNode(int data) { node *new_node = new node; new_node->data = data; new_node->next = NULL; return new_node; } /* displays the list elements */ void displayList(node *head) { cout << "Displaying List : "; while (head != NULL) { cout << head->data << " -> "; head = head->next; } cout << "NULL " << endl; } /* Search the node with element as data Return the pointer to the node if found else return NULL */ node *searchNode(node *head, int data) { node *ptr = NULL; while (head) { if (head->data == data) { ptr = head; break; } head = head->next; } return ptr; } /* insert a node at the beginning of the list */ node *insertNodeBeg(node *head, int data) { node *ptr = getNewNode(data); if (head == NULL) { // if list is empty head = ptr; } else { ptr->next = head; head = ptr; } return head; } /* insert a node at the end of the list */ node *insertNodeEnd(node *head, int data) { node *ptr = getNewNode(data); if (head == NULL) { //if list is empty head = ptr; } else { node *temp = head; while (temp->next != NULL) { // move to the last node temp = temp->next; } temp->next = ptr; // insert node at the end } return head; } /* insert a node at the after a particular node in the list */ node *insertNodeAfter(node *head, int element, int data) { // search the element after which node is to be inserted node *temp = searchNode(head, element); if (temp == NULL) { // element not found cout << "Element not found ... " << endl; } else { node *ptr = getNewNode(data); if (temp->next == NULL) { // node has to inserted after the last node temp->next = ptr; } else { // insert the node after the first or an intermediate node ptr->next = temp->next; temp->next = ptr; } } return head; } /* delete a particular node from the list */ node *deleteNode(node *head, int element) { node *temp = searchNode(head, element); // search the node to be deleted if (temp == NULL) { // element not found cout << "Node to be deleted not found ... " << endl; } else { if (temp == head) { // first node is to be deleted head = head->next; delete temp; } else { // node to deleted is an intermediate or last node node *ptr = head; while (ptr->next != temp) { ptr = ptr->next; } ptr->next = temp->next; delete temp; } } return head; } int main() { node *head = NULL; head = insertNodeBeg(head, 7); // 7 displayList(head); head = insertNodeBeg(head, 9); // 9 -> 7 displayList(head); head = insertNodeEnd(head, 11); // 9 -> 7 -> 11 displayList(head); head = insertNodeAfter(head, 9, 4); // 9 -> 4 -> 7 -> 11 displayList(head); head = insertNodeAfter(head, 7, 3); // 9 -> 4 -> 7 -> 3 -> 11 displayList(head); head = insertNodeAfter(head, 11, 6); // 9 -> 4 -> 7 -> 3 -> 11 -> 6 displayList(head); head = deleteNode(head, 7); // 9 -> 4 -> 3 -> 11 -> 6 displayList(head); head = deleteNode(head, 6); // 9 -> 4 -> 3 -> 11 displayList(head); head = deleteNode(head, 9); // 4 -> 3 -> 11 displayList(head); return 0; }

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