C++ array 探索1

template 
class Array
{
public:
    typedef Array                       __self;
    typedef T                           value_type;
    typedef value_type&                 reference;
    typedef const value_type&           const_reference;

    typedef value_type*                 iterator;
    typedef const value_type*           const_iterator;

public:
    Array(int size)
    {
        _size = size;
        _arr = new value_type[size];
    }
    ~Array()
    {
        delete[] _arr;
        _arr = nullptr;
    }

public:
    __self::iterator begin() throw()
    {
        return &_arr[0];
    }

    __self::iterator end() throw()
    {
        return &_arr[_size];
    }

    __self::reference operator[](int index) throw()
    {
        return _arr[index];
    }

    __self::const_reference operator[](int index) const throw()
    {
        return _arr[index];
    }

    __self::reference at(int index)
    {
        return _arr[index];
    }

    __self::const_reference at(int index) const
    {
        return _arr[index];
    }

    void operator()(int index, value_type val)
    {
        _arr[index] = val;
    } 

private:
    value_type       *_arr;
    int             _size;
};