"Jianli Shen" <ji****@cc.gatech.edu> wrote...
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?
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
