Реализация итераторов

#include <iostream>
#include <iterator>
#include <random>
using namespace std;
template<typename Type>
class Box {
public:
    using iterator = Type*;
    using const_iterator = const Type*;
    Box() : limit_(0U), ptr_(nullptr) { }
    explicit Box(const size_t limit) : limit_(limit) {
        ptr_ = new Type[limit_];
    }
    Box(initializer_list<Type> lst) : ptr_(new Type[lst.size()]), limit_(lst.size()) {
        copy(lst.begin(), lst.end(), this->begin());
    }

    Box(Box& box) {
        limit_= box.limit_;
        ptr_ = new Type[limit_];
        copy(box.begin(), box.end(), this->begin());
    }
    Box& operator=(Box& box) {
        if (this != &box) {
            if (ptr_) delete[] ptr_;
            limit_ = box.limit_;
            ptr_ = new Type[limit_];
            copy(box.begin(), box.end(), this->begin());
        }
        return *this;
    }
    ~Box() {
        if (ptr_) {
            delete[] ptr_;
            ptr_ = nullptr;
        }
    }
    int& operator[](const int index) {
        return ptr_[index];
    }
    const int& operator[](const int index)const {
        return ptr_[index];
    }
    size_t size()const {
        return limit_;
    }
    bool empty()const {
        return limit_ == 0U;
    }
    iterator begin()const {
        return ptr_;
    }
    iterator end()const {
        return ptr_ + limit_;
    }
    const_iterator cbegin()const {
        return ptr_;
    }
    const_iterator cend()const {
        return ptr_ + limit_;
    }
    auto rbegin()const {
        const reverse_iterator<iterator> ri(end());
        return ri;
    }
    auto rend()const {
        const reverse_iterator<iterator> ri(begin());
        return ri;
    }
    auto crbegin()const {
        const reverse_iterator<const_iterator> cri(rbegin());
        return cri;
    }
    auto crend()const {
        const reverse_iterator<const_iterator> cri(rend());
        return cri;
    }
private:
    size_t limit_;
    Type* ptr_;
};
int main() {
    Box<int> box = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    for (const auto value : box) cout << value << ' ';
    cout.put('\n');
    for (auto iter = box.crbegin(); iter != box.crend(); ++iter) cout << *iter << ' ';
    cout.put('\n');
    auto other = box;
    other[3] = 8;
    copy(other.cbegin(), other.cend(), ostream_iterator<int>(cout, " "));
    cout.put('\n');
    for (auto i = 0U; i < size(box); ++i) cout << box[i] << ' ';
    cout.put('\n');
    const uniform_int_distribution<> uid(1, static_cast<int>(size(other)));
    random_device rd;
    mt19937 gen(rd());
    generate(other.begin(), other.end(), [&]() { return uid(gen); });
    copy(other.rbegin(), other.rend(), ostream_iterator<int>(cout, " "));
    cout.put('\n');
    Box<int> tmp;
    tmp = other;
    for (auto iter = tmp.crbegin(); iter != tmp.crend(); ++iter) cout << *iter << ' ';
    cout.put('\n');
    system("pause");
}