Array in object doesn't duplicate upon instantiating

Question

I guess I'm victim of my own misunderstanding of OOP but can
somebody tell me why if I create two instances of an object which
itself creates another array object, I end up referencing the same
array ?
I've attached some oversimplified code to make things
clearer. Why are both arrays containing the same data ? Aren't they
different objects ?

Answer 1

> That's odd. Is there a reason why this would only happen
with the array
> class ?
It isn't only the array class. Its any object class
Reason is, that in Flash AS, the code on the RHS of the '='
for a var is
evaluated once when the class is defined.
So if you have
var s : String = "1234";
the "1234" is evaluated once (which is fine, its just a
constant) and the
result saved and set as the default values for the var for
each new
instance.
Similarly, if you have
var a : Array = new Array();
the 'new Array()' is evaluated once and the result saved and
set as the
default values for the var for each new instance.
As you may already know, if a and b are arrays, and you set a
= b; then a
will now refer to the identical array as b does (so changing
a changes b and
vice versa).
That means, if you use the above way of defining an array
variable (or
similarly for object), then each instance will have a
reference to the one
actual array.
To fix it, just declate
var a : Array;
and in the constructor function have
a = new Array();
that wat the 'new Array()' happens for each new instance of
the clase
(because the consutrctor function is run once for each new
instance).
Jeckyl