Re: Accessing a property of a returned object?
Re: Accessing a property of a returned object?
- Subject: Re: Accessing a property of a returned object?
- From: Graham Cox <email@hidden>
- Date: Sun, 27 Jul 2008 16:58:49 +1000
If a linked-list is the data structure that is the most natural fit,
why not just use a linked list? (i.e. don't bother with NSArray etc).
Objective-C is C, so you can do whatever you want - there's nothing to
say to *have* to use Cocoa containers. I occasionally use classic
linked lists in Cocoa code, they work fine.
Having said that, you can also link items that are in an array if that
is the best design, nothing to stop you.
I don't think your approach to actually linking the items is all that
smart though - normally managing linked lists is pretty
straightforward without having to defer stuff for one loop. Instead,
insert the new item into the linked list at the head or tail first and
then add it to the array, you should find there's no need for any
skanky accessors like this.
I'm not answering your actual question - sorry. I'm not familiar with
the Obj-C 2.0 property notation so I don't know the answer, but I
reckon a better approach to the design will make the need go away
anyway.
hth,
Graham
On 27 Jul 2008, at 4:33 pm, Mark Teagarden wrote:
Hi,
I'm working on a strategy game in which a NSMutableArray called
'army' contains a series of Unit objects. Each Unit contains a
property called next_unit, which is a pointer to the next unit in
the array - I'm implementing a linked-list so that units can be
moved sequentially.
Army starts off with six units, which are assigned one at a time to
the array:
for(i=0;i<6;i++){
u = [[Unit alloc] initWithPositionX:24+i Y:14-i];
[army addObject:u];
...
[u release];
}
Obviously when the first unit is added, there's nothing for
next_unit to point to, so I have to go back and do it on the next
loop iteration, which is where my problem arises:
if(i > 0) [army objectAtIndex:i-1].next_unit = [army lastObject];
Clearly, what I want to do is get the next-to-last unit in army and
point its next_unit pointer to the most recently added unit.
However, XCode she don't-a like this:
error: request for member 'next_unit' in something not a structure
or union
Is there a recommended way for accessing an ivar with synthesized
gettors/settors, that belongs to a returned object?
I hope I've explained my problem clearly enough. Thanks for an
advice you may offer.
Mark
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