#include <iostream>

template<class T>
class LinkedList {
public:
    LinkedList();
    LinkedList(T);
    ~LinkedList();

    void add(T);
    T pop();
private:
    struct Node {
        T data;
        struct Node* next;
    };

    struct Node* head;
};

template <class T>
LinkedList<T>::LinkedList(){
    head = nullptr;
}

template <class T>
LinkedList<T>::LinkedList(T data) {
    head = new struct Node;
    head->data = data;
    head->next = nullptr;
}

template <class T>
LinkedList<T>::~LinkedList() {
    while (head != nullptr) {
        pop();
    }
}

template <class T>
void LinkedList<T>::add(T data) {
    struct Node *newnode = new struct Node;
    newnode->data = data;
    newnode->next = head;

    head = newnode;
}

template <class T>
T LinkedList<T>::pop() {
    T data = head->data;

    struct Node* popper = head;
    head = head->next;

    delete popper;

    return data;
}

int main() {
    LinkedList<int> myLinkedList(10);
    myLinkedList.add(20);
    myLinkedList.add(30);

    // Prints 30
    std::cout << myLinkedList.pop() << std::endl;

    // Prints 20
    std::cout << myLinkedList.pop() << std::endl;

    // Prints 10
    std::cout << myLinkedList.pop() << std::endl;

    return 0;
}