Linked_List.cpp

#include <iostream>
using namespace std;

struct Node{
    int data;
    Node *next;

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

class linkedList{
private:
    Node *head;
public:

    linkedList(){
        head = nullptr;
    }

    bool isEmpty(){
        return head == nullptr;
    }

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

    void printList(){
        Node *current = head;
        while(current != nullptr){
            cout << current->data << " -> ";
            current = current->next;
        }
        if (current == nullptr){
            cout << "NULL" << endl;
        }
    }

    bool isFound(int item){
        Node *current = head;
        while(current != nullptr){
            if (current->data == item){
                return true;
            }
            else{
                current = current->next;
            }
        }
        if (current == nullptr){
            return false;
        }
    }

    void insertBefore(int item, int val){
        Node *newNode = new Node(val);
        Node *temp = head;

        while (temp->next->data != item & temp != nullptr){
            temp = temp->next;
        }
        newNode->next = temp->next;
        temp->next = newNode;
    }

    void append(int val){
        Node *newNode = new Node(val);
        if(isEmpty()){
            head = newNode;
        }
        else {
            Node *temp = head;
            while (temp->next != nullptr){
                temp = temp->next;
            }
            temp->next = newNode;
        }
    }

    void Delete(int item){
        if(isEmpty()){
            return;
        }
        if(head->data == item){
            Node *delptr = head;
            head = head->next;
            delete delptr;
        }
        else{
            Node *delptr = head;
            Node *prev = head;
            while (delptr->data != item){
                prev = delptr;
                delptr = delptr->next;
            }
            prev->next = delptr->next;
            delete delptr;
        }
    }


};

int main() {

    linkedList list;


    list.insertFirst(10);
    list.insertFirst(20);
    list.insertFirst(40);
    list.printList();
    list.insertBefore(20,5);
    list.printList();
    list.append(9);
    list.append(2);
    list.append(0);
    list.printList();
    list.Delete(40);
    list.printList();

    cout << "Is the list empty? " << (list.isEmpty() ? "Yes" : "No") << endl;
    cout << "Is the item found? " << (list.isFound(20) ? "Yes" : "No") << endl;

    return 0;

}