• Open Menu Close Menu
  • Apple
  • Shopping Bag
  • Apple
  • Mac
  • iPad
  • iPhone
  • Watch
  • TV
  • Music
  • Support
  • Search apple.com
  • Shopping Bag

Lists

Open Menu Close Menu
  • Terms and Conditions
  • Lists hosted on this site
  • Email the Postmaster
  • Tips for posting to public mailing lists
Re: Best way to compare CGFloats (Rick B.)
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Best way to compare CGFloats (Rick B.)


  • Subject: Re: Best way to compare CGFloats (Rick B.)
  • From: Alastair Houghton <email@hidden>
  • Date: Wed, 30 Jun 2010 20:35:56 +0100

On 30 Jun 2010, at 17:37, Michael Ash wrote:

> While we're being pedantic, note that == is not always the same as
> "binary equivalence". For example, 0.0 == -0.0, and x != x when x =
> NAN.

That's a good point.  I spoke inaccurately.

> Using == can make sense when you know that your values are exact
> integers, which is not an uncommon scenario, but neither is it the
> usual one.

It may also make sense sometimes with floating point values.  An example might be where you have an object that you're using as the key for an NSDictionary; in that case, your -isEqual: method may well want to do a proper equality test.

These are, however, special situations.

Kind regards,

Alastair.

--
http://alastairs-place.net




_______________________________________________

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

References: 
 >Re: Best way to compare CGFloats (Rick B.) (From: Frederick Bartram <email@hidden>)
 >Re: Best way to compare CGFloats (Rick B.) (From: Alastair Houghton <email@hidden>)
 >Re: Best way to compare CGFloats (Rick B.) (From: Michael Ash <email@hidden>)

  • Prev by Date: Re: NSOpenPanel won't allow selecting aliases
  • Next by Date: class_respondsToSelector() in runtime.h?
  • Previous by thread: Re: Best way to compare CGFloats (Rick B.)
  • Next by thread: Calling javascript from Cocoa 'facelessly'
  • Index(es):
    • Date
    • Thread