#pragma once

template <class T>
struct List {
    struct Container {
        T* t;
        Container* next = nullptr;
        Container(T* t) : t(t) {}
    };

    Container* first = nullptr;
    Container* last = nullptr;

    void add(T* t) {
        Container* c = new Container{t};
        first == nullptr ? first = c : last->next = c;
        last = c;
    }

    void forEach(void(*f)(T*)) {
        for (Container *c = first; c; c = c->next) {
            f(c->t);
        }
    }

    void empty() {
        Container *c = first;
        while (c) {
            auto n = c->next;
            delete c;
            c = n;
        }
    }

};