在C++ 2011中创建自定义随机访问迭代器

Question

我想对我的代码发表意见。我需要一个随机访问迭代器来定制容器。 如果我读的C++标准2011，特别是第24章，我明白了一个实现 可能是以下几点：

class my_iterator : public std::iterator<std::random_access_iterator_tag, my_element> 
{ 
    private: 
     my_container *_ref; 
     my_iterator_state state; // some useful state 
    public: 
     my_iterator(); 
     my_iterator (const my_iterator &); 
     my_iterator (my_iterator &&); 
     ~my_iterator(); 
     my_iterator &operator = (const my_iterator &); 
     my_iterator &operator = (my_iterator &&); 
     reference operator *(); 
     my_iterator &operator ++(); 
     bool operator != (my_iterator); 
     value_type operator *(); 
     pointer operator ->(); 
     my_iterator &operator *(); 
     void operator ++ (int); 
     value_type operator ++ (int); 
     const my_iterator &operator ++ (int); 
     reference operator ++ (int); 
     my_iterator &operator --(); 
     const my_iterator operator -- (int); 
     reference operator -- (int); 
     my_iterator &operator += (difference_type); 
     my_iterator operator + (difference_type); 
     my_iterator operator - (difference_type); 
     reference operator [] (difference_type); 
     bool operator < (my_iterator); 
     bool operator > (my_iterator); 
     bool operator <= (my_iterator); 
     bool operator >= (my_iterator); 
     friend difference_type (my_iterator, my_iterator); 
     friend my_iterator operator + (difference_type, my_iterator); 
     friend void swap (iterator &, iterator &); 
}; 

void swap (iterator &, iterator &); 
difference_type (my_iterator, my_iterator); 
my_iterator operator + (difference_type, my_iterator); 

以上实施是正确的，功能齐全，？有太多成员？

Answer 1

一般来说，您不能使用具有相同参数但返回类型不同的重载，因此您的几个成员不能存在。你应该记住以下：

reference operator *(); 
my_iterator operator ++ (int); 
my_iterator operator -- (int); 

并取出假重载：

value_type operator *(); 
void operator ++ (int); 
value_type operator ++ (int); 
const my_iterator &operator ++ (int); 
reference operator ++ (int); 
const my_iterator operator -- (int); 
reference operator -- (int); 

这是没有意义的：

friend difference_type (my_iterator, my_iterator); 

，我认为应该是：

friend difference_type operator-(my_iterator, my_iterator); 

，你似乎失踪了operator-=