| Re: array of objects? [message #29276] |
Tue, 12 February 2002 09:22  |
Pavel A. Romashkin
Messages: 531
Registered: November 2000
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Senior Member |
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Ted is correct. For creating an array of objects, you need to use OBJARR
function, then loop through the array and populate each element using
OBJ_NEW. What you have created in your code is 100 references to the
same object.
We talked before about the advantages of allowing definitions of object
arrays the same way as normal arrays are made, but the consensus was
that it is unsafe :( becasuse, say, one could populate an object array
with different object classes. Personally, I think it is not so and I'd
leave that decision to the programmer, but heap variable arrays are
slower a bit anyway, so none of the fast vector features of IDL would've
worked on them anyway.
HTH,
Pavel
Thomas Bielser wrote:
>
> ...but IDL comes up with:
>
> IDL> print, a[0] -> getproperty( /integer_value )
> 99
> IDL> print, a[50] -> getproperty( /integer_value )
> 99
> IDL> print, a[99] -> getproperty( /integer_value )
> 99
>
> Is this a feature or a bug? Many thanks in advance!
> Thomas
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| Re: array of objects? [message #29366 is a reply to message #29276] |
Tue, 12 February 2002 23:19  |
thomas.bielser
Messages: 2
Registered: February 2002
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Junior Member |
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Thanks to Ted and Pavel: Your were absolutely right!
After creating the array with 100 elements (each with a null pointer):
; array for holding 100 elements of the type 'own_class'
a = OBJARR( 100 )
I added the following statement in the loop, which runs over all the elements:
; label each array-element with it's number
for i=0, 99 do begin
; create a new object and put the point to it via the variable "a"
a[ i ] = OBJNEW( 'own_class')
; call the method setproperty
a[ i ] -> setproperty, integer_value = i
endfor
Afterwards I had the expected output as mentioned in my former posting.
Cheers,
Tom
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