问我的迭代器实现不起作用，有什么问题吗？

EN

#include <iostream>
template<typename T>
class iter final {
private:
    T* current_ = nullptr;
    T* end_ = nullptr;
    int n;
public:
    iter(T* first) :current_(first) {};
    iter() {};
    inline T& operator+ (int n) { return *(current_ - n); }
    inline T& operator- (int n) { return *(current_ - n); }

    inline T& operator++ (int) { return *current_++; }
    inline T& operator-- (int) { return *current_--; }
    inline T& operator++ () { return *++current_; }
    inline T& operator-- () { return *current_--; }

    inline bool operator!= (const iter& it) { return current_ != it.current_; }
    inline bool operator== (const iter& it) { return current_ == it.current_; }

    inline T& operator* () { return *current_; }

    inline iter<T>* begin() { return current_; }
    inline iter<T>* end() { return end_ + n; }
    inline void set_current(T* _current) { current_ = _current; }
    inline void set_end(T* _end) { end_ = _end; n = (end_ - current_) / sizeof(_end); }
    inline void set_num(int num) { n = num; }
};
template<typename T>
class shuffle_range final {
public:
    shuffle_range() { it = new iter<T>; };
    ~shuffle_range() { delete it; };
    iter<T>* it;
};
template<typename T>
iter<T>* make_shuffle(T* begin, T* end) {
    static shuffle_range<T> shuffler;

    shuffler.it->set_current(begin);
    shuffler.it->set_end(end);
    shuffler.it->set_num(end - begin);
    return shuffler.it;
}

int main() {
    int a[] = { 0, 4, 5, 2, 8, 1 };
    auto shuffle_a = make_shuffle(a, (a + 5));
    for (auto i : shuffle_a)
        std::cout << i << " ";
    return 0;
}