task-1.cpp

#include <iostream>
#include <string>
using namespace std;



class Node {
    public:
        int data;
        Node* next;

        Node(int val) {
            data = val;
            next = nullptr;
        }
};


class SinglyLinkedList {
    private:
        Node* head;

    public:
        SinglyLinkedList() {
            head = nullptr;
        }

        void insertAtHead(int val) {
            Node* newNode = new Node(val);
            newNode->next = head;
            head = newNode;
        }

        void insertAtTail(int val) {
            Node* newNode = new Node(val);

            if (head == nullptr) {
                head = newNode;
                return;
            }

            Node* temp = head;
            while (temp->next != nullptr) {
                temp = temp->next;
            }
            
            temp->next = newNode;
        }

        void display() {
            Node* temp = head;
            while (temp!=nullptr)
            {
                cout << temp->data << " -> ";
                temp = temp->next;
            }
            cout << "NULL\n";
        }

        bool search(int val) {
            Node* temp = head;
            while (temp != nullptr) 
            {
                if (temp->data = val) return true;
                temp = temp->next;
            }
            return false;
        }

        void deleteNode(int val) {
            if (head==nullptr) return;

            if (head->data == val) {
                Node* toDelete = head;
                head = head->next;
                delete toDelete;
                return;
            }

            Node* temp = head;
            while (temp->next != nullptr && temp->next->data != val) 
            {
                temp = temp->next;
            }
            
            if (temp->next == nullptr) return;

            Node* toDelete = temp->next;
            temp->next = temp->next->next;
            delete toDelete;
        }
};

int main() {
    SinglyLinkedList list;

    // Insert at tail
    list.insertAtTail(10);
    list.insertAtTail(20);
    list.insertAtTail(30);

    // Insert at head
    list.insertAtHead(5);

    // Delete 20
    list.deleteNode(20);

    // Display
    list.display();  // EXPECT: 5 -> 10 -> 30 -> NULL

    // Search for 30
    cout << "Search 30: " << (list.search(30) ? "Found" : "Not Found") << endl;

    return 0;
}