nested class in c++

zlly20

IN C++ , what is the best way to allow nested class to access the member of outer class...

thanks

manphiz

Nested class has the permission to access the member of the class it nested in according to the C++ ISO/IEC 14882:2003 standard.

You can check it in
http://gcc.gnu.org/bugs.html
Non-bugs->C++ section.

zlly20

but it seems that this is not true
consider the following example

[PHP]

class A
{
public:
     A();
     
     class AInner
     {
      public:
           AInner();

           void AAccessor();
     };
private:
      int ToBeAccessed;
};

void A::AInner::AAccessor()
{
      ToBeAccessed += 1;
}

[/PHP]

when the above code is compiled, an error is returned by compiler:
error: ToBeAccessed is not a member of A::AInner

rickxbx

可以访问，但不是象你这样访问，如下：

2. class A
3. {
4. public:
5.      A();
6.      
7.      class AInner
8.      {
9.       public:
10.            AInner();
12.            void AAccessor();
13.      };
14. private:
15.       int ToBeAccessed;
16. };
18. void A::AInner::AAccessor()
19. {
20.       A a;
21.       a.ToBeAccessed += 1;
22. }

复制代码

zlly20

what if I don't have the instance of A (means I don't want to have a), are there any other ways to access A's attributes in AInner class ?

rickxbx

没有实例，哪来的实例的成员（静态成员除外）？