WeakRefList

#include <deque>
#include <cstdlib>

template<typename T>
class WeakRefList {
    std::deque<T*> storage;
public:
    class iterator_type {
        typename std::deque<T*>::iterator_type internal_iterator;
    public:
        iterator_type(typename std::deque<T*>::iterator_type it) :internal_iterator(it) {}

        T &operator*() {
            return **internal_iterator;
        }

        iterator_type operator++(int) {
            iterator_type copy(*this);
            ++internal_iterator;
            return copy;
        }

        iterator_type &operator++() {
            ++internal_iterator;
            return *this;
        }

        T *operator->() {
            return *internal_iterator;
        }
    };

    iterator_type begin() {
        return iterator_type(storage.begin());
    }

    iterator_type end() {
        return iterator_type(storage.end());
    }

    void push_back(T &elem) { storage.push_back(&elem); }
    void push_front(T &elem) { storage.push_front(&elem); }
    T &at(size_t i) { return *storage.at(i); }
    T &operator[](size_t i) { return *storage[i]; }

    void pop_back() { storage.pop_back(); }
    void pop_front() { storage.pop_front(); }
};