shared_ptr() = default;
    explicit shared_ptr(T *cur_ptr)
        : ptr_on_object(std::exchange(cur_ptr, nullptr)),
          use_count(new int{1}) {
    }
    explicit shared_ptr(std::nullptr_t) {
    }
    shared_ptr(const shared_ptr &other)
        : ptr_on_object(other.ptr_on_object),
          // cppcheck-suppress copyCtorPointerCopying
          use_count(other.use_count) {
        if (use_count != nullptr) {
            ++*use_count;
        }
    }
    shared_ptr(shared_ptr &&other)
        : ptr_on_object(std::exchange(other.ptr_on_object, nullptr)),
          use_count(std::exchange(other.use_count, nullptr)) {
    }
    shared_ptr &operator=(const shared_ptr &other) {
        if (other.ptr_on_object == ptr_on_object) {
            return *this;
        }
        delete_data();
        ptr_on_object = other.ptr_on_object;
        use_count = other.use_count;
        if (use_count != nullptr) {
            ++*use_count;
        }
        return *this;
    }
    shared_ptr &operator=(shared_ptr &&other) {
        if (other.ptr_on_object == ptr_on_object) {
            return *this;
        }
        delete_data();
        ptr_on_object = std::exchange(other.ptr_on_object, nullptr);
        use_count = std::exchange(other.use_count, nullptr);
        return *this;
    }
    ~shared_ptr() {
        delete_data();
    }