| re: can a class definition inside another class's definition
"Jianli Shen" <jianli@cc.gatech.edu> wrote...[color=blue]
> I want to implement like this:
>
> class A{
>
> int length;
>
> class B{
> void operate_length_in_A(){
> length++;
> }
>
> void use_length_in_A(){
> if(length>8){
> }
> }
>
> B *Bobj;
>
> }
>
> because B will use member in A, so I think I can not put B ahead of
> definition of A.
>
> How can I do?[/color]
Contrary to Java where a nested class is automatically instantiated as
a member of the outer class and also gets all members of the outer class
accessible and associated with the same instance of the outer class as
the nested instance, in C++ a nested class definition is nothing but
a definition of a type.
If you need to access non-static data members of the outer class (like
'length' in your example) from a function that is not a non-static member
of that outer class, you would need an instance to go along with it:
...
class B {
void operate_length_in_A(A& a) {
a.length++;
}
...
Where you put the definition of B inside A shouldn't matter.
V
| 
