[MinGW-notify] [ mingw-Bugs-3517140 ] wrong double representation

[SF/projects/mingw n. l. <min...@li...>]

Bugs item #3517140, was opened at 2012-04-12 02:41
Message generated for change (Comment added) made by earnie
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=102435&aid=3517140&group_id=2435

Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: gcc
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Gaetano  (executive2002)
>Assigned to: Cesar Strauss (cstrauss)
Summary: wrong double representation

Initial Comment:
Hi,
I am experiencing problems in a C++ program due to wrong representation on a double variabile.
I'm using: Windows 7 Enterprise 64 bit

gcc -v
C:\Users\Gaetano>gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=c:/mingw/bin/../libexec/gcc/mingw32/4.6.2/lto-wrapper.exe
Target: mingw32
Configured with: ../gcc-4.6.2/configure --enable-languages=c,c++,ada,fortran,objc,obj-c++ --disable-
sjlj-exceptions --with-dwarf2 --enable-shared --enable-libgomp --disable-win32-registry --enable-lib
stdcxx-debug --enable-version-specific-runtime-libs --build=mingw32 --prefix=/mingw
Thread model: win32
gcc version 4.6.2 (GCC)

As IDE, I use Eclipse for C/C++.

Definition:
float TagliMonete[] = {2.0, 1.0, 0.5, 0.2, 0.1, 0.05, 0.02, 0.01 };

From TagliMonete[0]-TagliMonete[2] everything (in memory) is ok.
TagliMonete[3] is represented in memory as 0.2000000003
TagliMonete[4] is represented in memory as 0.1000000001
TagliMonete[5] is represented in memory as 0.05000000007
TagliMonete[6] is represented in memory as 0.01999999996
TagliMonete[7] is represented in memory as 0.00999999978

I've seen these values in Debug mode.

This is a very big problem due to problem on contabilization.

How can I supersede the problem? 

Thanks a lot.


----------------------------------------------------------------------

>Comment By: Earnie Boyd (earnie)
Date: 2012-04-12 06:05

Message:
Please attach a small code working model that represents the problem with
steps to recreate the problem using that working model.

----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=102435&aid=3517140&group_id=2435