linked_list.java

class Node {
    int data;
    Node next;

    Node(int data) {
        this.data = data;
        this.next = null;
    }
}

class LinkedList {
    Node head;

    // Insert an element at the end of the linked list
    void append(int data) {
        Node newNode = new Node(data);
        if (head == null) {
            head = newNode;
            return;
        }
        Node current = head;
        while (current.next != null) {
            current = current.next;
        }
        current.next = newNode;
    }

    // Delete the first occurrence of a value in the linked list
    void delete(int data) {
        if (head == null) {
            return;
        }
        if (head.data == data) {
            head = head.next;
            return;
        }
        Node current = head;
        while (current.next != null) {
            if (current.next.data == data) {
                current.next = current.next.next;
                return;
            }
            current = current.next;
        }
    }

    // Display the linked list
    void display() {
        Node current = head;
        while (current != null) {
            System.out.print(current.data + " -> ");
            current = current.next;
        }
        System.out.println("null");
    }
}

public class Main {
    public static void main(String[] args) {
        LinkedList linkedList = new LinkedList();
        linkedList.append(1);
        linkedList.append(2);
        linkedList.append(3);
        linkedList.display(); // Output: 1 -> 2 -> 3 -> null
        linkedList.delete(2);
        linkedList.display(); // Output: 1 -> 3 -> null
    }
}