iterator和const_iterator以及节点Node是类List中嵌套类
iterator继承来自const_iterator
const_iterator里面有Node* current变量以及retrieve()函数
重点来了!!!!!!!!!!!!!!!!!!!
iterator好像看不到上述的那个变量以及函数
编译器一直报错
希望高手帮忙指点一下(限于篇幅已经把一些不相关的函数已经删除)
#include
using namespace std;
template
class List{
private:
struct Node
{
Object data;
Node *prev;
Node *next;
Node(const Object&d=Object(),Node *p=NULL,Node *n=NULL)
:data(d),prev(p),next(n){}
};
public:
class const_iterator
{
public:
const_iterator():current(NULL)
{}
protected://
Node *current;
Object &retrieve()const
{
return current->data;
}
const_iterator(Node *p):current(p)
{}
friend class List<Object>;
};
class iterator:public const_iterator
{
public:
iterator()
{}
Object & operator*()
{
return retrieve();//
/*
List.cpp:64:37: error: there are no arguments to ‘retrieve’ that depend on a template parameter, so a declaration of ‘retrieve’ must be available [-fpermissive]
return retrieve();
*/
}
const Object& operator*()const
{
return const_iterator::operator*();
}
iterator &operator++()
{
current = current->next; //////// 看不到current
return *this;
/*List.cpp:64:37: note: (if you use ‘-fpermissive’, G++ will accept your code, but allowing the use of an undeclared name is deprecated)
List.cpp: In member function ‘List::iterator& List::iterator::operator++()’:
List.cpp:72:21: error: ‘current’ was not declared in this scope
/
}
iterator operator++(int)
{
iterator old = *this;
++(*this);
return old;
}
protected:
iterator(Node p):const_iterator(p)
{}
friend class List<Object>;
};
public:
private:
int theSize;
Node *head;
Node *tail;
};
int main()
{
return 0;
}
