在C++ 2011中創建自定義隨機訪問迭代器

Question

我想對我的代碼發表意見。我需要一個隨機訪問迭代器來定製容器。 如果我讀的C++標準2011，特別是第24章，我明白了一個實現 可能是以下幾點：

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); 

以上實施是正確的，功能齊全，？有太多成員？

Answer 1

一般來說，您不能使用具有相同參數但返回類型不同的重載，因此您的幾個成員不能存在。你應該記住以下：

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

並取出假重載：

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); 

這是沒有意義的：

friend difference_type (my_iterator, my_iterator); 

，我認爲應該是：

friend difference_type operator-(my_iterator, my_iterator); 

，你似乎失蹤了operator-=