Re: g++/gcc : Floating point issue

[Daniel Llorens del Río <daniel dot llorensdelrio at epfl dot ch>]

On 26 Jul, 2006, at 16:52, abuzer.salik@tcs.com wrote:

> Hi,
>
> I have an application which uses double values a lot. If I try to  
> put say
> 401.74 in a double variable it is getting stored as 401.74000000000001
> which creates problem in the calculations down the line. ( I am  
> checking
> these values using gdb debugger).
>
> So, I am wondering if there is a way by which I can store the correct
> values (i.e. 401.74) in the double.

Use a library of rationals if you need exact values, I think GMP  
provides one.

> Do we need to look for another compiler/hardware or current setup can
> handle this?

As long as you use doubles, which are tied to the hardware, you'll  
have the same problem. The precision is more or less standard across  
architectures. IOW it has little to do with the compiler.