# Re: [go-nuts] Re: Float multiplication bug?

```This question is already answered, but i was on a plane and added a bit to
the printing and the comments. in case anyone ever refers to this thread in
the future, this is the better version of the program to run:
https://play.golang.org/p/EK0XMnMUKwv```
```
On Fri, Feb 23, 2018 at 8:06 AM, Michael Jones <michael.jo...@gmail.com>
wrote:

> One subtle thing is the difference between an ideal number, its
> floating-point representation, and its printed form.
>
> On Fri, Feb 23, 2018 at 5:46 AM, <steve_bagw...@sil.org> wrote:
>
>> Thanks guys. That's very helpful.  I forgot that what I saw (and re-used)
>> as the "height" was not precise enough to make it comparable.
>>
>>
>> On Thursday, February 22, 2018 at 3:33:38 PM UTC-5, Steve Bagwell wrote:
>>>
>>>
>>>  Hello Everyone,
>>>
>>>  This looks like a Golang bug to me. What do you all think?
>>>
>>>>  I have this function ...
>>>
>>> func getArea(base, side int64) float64 {
>>>> var height, fSide, area float64
>>>> fSide = float64(side)
>>>> halfBase := float64(base) / 2.0
>>>> height = math.Sqrt(fSide*fSide - halfBase*halfBase)
>>>> area = halfBase * height
>>>> fmt.Printf("halfBase: %f, height: %f, Area: %f\n", halfBase, height,
>>>> area)
>>>>
>>>
>>>
>>>>         hb2 := 151414.5
>>>>         h2 := 262256.452301
>>>>         fmt.Printf("Area 2: %f\n", hb2 * h2)
>>>>
>>>
>>>
>>>> return area
>>>> }
>>>
>>>
>>> When I call it with `result := getArea(302829, 302828)`,   I get this
>>> output ...
>>>
>>> halfBase: 151414.500000, height: 262256.452301, Area: 39709429597.000000
>>>> Area 2: 39709429596.929764
>>>
>>>
>>> I could see how some kind of rounding could produce the first Area
>>> value.  But in that case, why wouldn't Area2 be rounded as well?
>>>
>> --
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>
>
>
> --
> Michael T. Jones
> michael.jo...@gmail.com
>

--
Michael T. Jones
michael.jo...@gmail.com

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