[erlang-questions] In Erlang , {1.1*1.1.} show me the answer is 1.2100000000000002, why?

[Dmytro Lytovchenko]

Because of the principle how floating point numbers work. Encoded number is
approximate, so that 0.0000000002 is just closest representation in binary
that would encode your given fraction (1.21), and it is below the precision
which is guaranteed for this size of floating point value. This question
been discussed million times for every programming language.

http://en.wikipedia.org/wiki/IEEE_floating_point (there is chinese variant
of this article, hope its detailed enough).

On Sun, Oct 26, 2014 at 8:24 AM, 张栋 <zd2559@REDACTED> wrote:

> Hello the maillist member:
> I am  new in Erlang,Please Help me.
>
> When I try some multiplication, I got the some unexpected answer about
> the following expression.
>
> Please help!
>
> List:
>
> 23> [1.1*1.1,1.1*1.2,1.1*1.3,1.1*1.4,1.1*1.5].
> [1.2100000000000002,1.32,1.4300000000000002,1.54,
>  1.6500000000000001]
>
> 24> [1.2*1.2,1.2*1.3,1.2*1.4,1.2*1.5,1.2*1.6].
> [1.44,1.56,1.68,1.7999999999999998,1.92]
>
> Thank you for your time.
>
> Eric D. Zhang In China.
>
>
>
>
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