Hi, I have the following problem:

I need to change the precision of double variable, but I don't want to
round it. Just cut unnecessary part.
For example:

I have: double d=0.3999999

I wan't to have: 0.39

Is there any method in .NET Framework that could help me?

Hello,

just call Math.Round(d, 2);

Kind regards,
Henning Krause

 wrote in message 
news:1184835109.474544.22960@i13g2000prf.googlegroups.com...

> Hi, I have the following problem:
>
> I need to change the precision of double variable, but I don't want to
> round it. Just cut unnecessary part.
> For example:
>
> I have: double d=0.3999999
>
> I wan't to have: 0.39
>
> Is there any method in .NET Framework that could help me?
> 

Hi Henning,

I'm pretty sure that the result of Math.Round(0.39999999999, 2) == 0.4
and not 0.39. However, the following does work:

double value = 0.399999999999;
double rounded = Math.Round(value * 100.0) / 100.0;

Kind regards,
Bram Fokke

On 19 jul, 11:37, "Henning Krause [MVP - Exchange]"
 wrote:

> Hello,
>
> just call Math.Round(d, 2);
>
> Kind regards,
> Henning Krause
>
>  wrote in message
>
> news:1184835109.474544.22960@i13g2000prf.googlegroups.com...
>
> > Hi, I have the following problem:
>
> > I need to change the precision of double variable, but I don't want to
> > round it. Just cut unnecessary part.
> > For example:
>
> > I have: double d=0.3999999
>
> > I wan't to have: 0.39
>
> > Is there any method in .NET Framework that could help me?

wrote:

> I need to change the precision of double variable, but I don't want to
> round it. Just cut unnecessary part.


It's not really clear what you mean.


> For example:
> 
> I have: double d=0.3999999
> 
> I wan't to have: 0.39


Isn't that just rounding it though? Could you give more information 
about what you're trying to achieve?

-- 
Jon Skeet - 
http://www.pobox.com/~skeet   Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

Based on the OP's request, Math.Truncate is what is needed.

  double value = 0.3999999;
  double new_value = Math.Truncate(value * 100.0) / 100.0;

The code above sets new_value to 0.39.


"mamin@o2.pl" wrote:


> Hi, I have the following problem:
> 
> I need to change the precision of double variable, but I don't want to
> round it. Just cut unnecessary part.
> For example:
> 
> I have: double d=0.3999999
> 
> I wan't to have: 0.39
> 
> Is there any method in .NET Framework that could help me?
> 
> 

"Bram" wrote:


> Hi Henning,
> 
> I'm pretty sure that the result of Math.Round(0.39999999999, 2) == 0.4
> and not 0.39. However, the following does work:
> 
> double value = 0.399999999999;
> double rounded = Math.Round(value * 100.0) / 100.0;
> 
> Kind regards,
> Bram Fokke


On my machine, the code above sets rounded to 0.4, the same as in your first 
example.


> 
> On 19 jul, 11:37, "Henning Krause [MVP - Exchange]"
>  wrote:
> > Hello,
> >
> > just call Math.Round(d, 2);
> >
> > Kind regards,
> > Henning Krause
> >
> >  wrote in message
> >
> > news:1184835109.474544.22960@i13g2000prf.googlegroups.com...
> >
> > > Hi, I have the following problem:
> >
> > > I need to change the precision of double variable, but I don't want to
> > > round it. Just cut unnecessary part.
> > > For example:
> >
> > > I have: double d=0.3999999
> >
> > > I wan't to have: 0.39
> >
> > > Is there any method in .NET Framework that could help me?
> 
> 
> 

mamin@o2.pl wrote:

> Hi, I have the following problem:
> 
> I need to change the precision of double variable, but I don't want to
> round it. Just cut unnecessary part.
> For example:
> 
> I have: double d=0.3999999
> 
> I wan't to have: 0.39
> 
> Is there any method in .NET Framework that could help me?
> 


maybe String.Format({0:n2}, myDouble);

is what you want.