#include "iostream"

template <class T>

struct ListItem {

ListItem<T>* next;

ListItem<T>* prev;

T data;

};

template <class T>

class List {

private:

ListItem<T>* head;

ListItem<T>* tail;

public:

List<T>() {

head = NULL;

tail = NULL;

};

void push(T value) {

ListItem<T>* item = new ListItem<T>;

item->data = value;

if (head == NULL) {

head = item;

} else {

item->prev = tail;

tail->next = item;

}

tail = item;

}

void display() {

ListItem<T>* current = head;

while (current != NULL) {

std::cout << current->data << '\n';

current = current->next;

}

}

};

int main() {

List<std::string> list;

list.push("Ave");

list.push("Emperor");

list.push("Marcus Aurelius!");

list.display();

};