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Re: why are floats flakey?
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Re: why are floats flakey?


  • Subject: Re: why are floats flakey?
  • From: Andrew Thompson <email@hidden>
  • Date: Mon, 24 May 2004 23:41:00 -0400

On May 24, 2004, at 10:23 PM, justin webster wrote:

why are floats inaccurate?
when can I use them with confidence and what can I use in their place when I need absolute accuracy?

i'm trying to create a float with a value of 29.97 and I get 29.9699999
like this:
float myFloat = [myTextField floatValue]
where the text field contains the string "29.97df"

Don't use floats if you need precise accuracy. Find a fixed precision decimal representation.
This is not Cocoa specific, its common to most modern languages on most modern CPUs

Research two's complement notation and IEEE 754 (try google) for background info.

AndyT (lordpixel - the cat who walks through walls)
A little bigger on the inside

(see you later space cowboy ...)
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References: 
 >why are floats flakey? (From: justin webster <email@hidden>)

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