Re: App Crashing when remove an Object
Re: App Crashing when remove an Object
- Subject: Re: App Crashing when remove an Object
- From: "Sherm Pendley" <email@hidden>
- Date: Fri, 28 Mar 2008 21:08:51 -0400
On Fri, Mar 28, 2008 at 8:49 PM, Andrew Farmer <email@hidden> wrote:
> On 28 Mar 08, at 18:37, Mario Gajardo Tassara wrote:
> > In a portion of code of my app (collision detection part) i need to
> > remove an object from an array of objects,
> > when two distinct objects crashed i decrement a life counter, and
> > if this is equal to zero the object must be destroyed, but when the
> > counter
> > reach de zero and the object is destroyed my app crash. Some one can
> > help me with this problem, here is the code, and thanks in advance:
>
> You're removing an object from an array while iterating through it.
> Think carefully about what this is doing to the indexes of objects in
> the array, and you'll probably see what's going on.
>
> You probably ought to move to some sort of "mark-and-sweep" algorithm
> here, rather than mutating the array while iterating through it.
No argument here.
But, if you *do* want to mutate an array while iterating through it, a
common approach is to iterate through it backwards. That way, deleting an
element will only shift the elements at indexes you've already touched.
sherm--
>
> _______________________________________________
>
> Cocoa-dev mailing list (email@hidden)
>
> Please do not post admin requests or moderator comments to the list.
> Contact the moderators at cocoa-dev-admins(at)lists.apple.com
>
> Help/Unsubscribe/Update your Subscription:
>
> This email sent to email@hidden
>
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden