atof() failure case

[Sreekanth]

Hello,
Am trying to convert a string to float. Am using atof() for that purpose.
But the return value for atof is same for the string "0.0" and for some
invalid input "Invalid". Can any body suggest me the way to differentiate an
invalid float number string and a 0.0.
TIA,
Sreekanth.

[Irrwahn Grausewitz]

Re: atof() failure case

"Sreekanth" <sreekanth@yaho o.com> wrote:[color=blue]
>Hello,
>Am trying to convert a string to float. Am using atof() for that purpose.
>But the return value for atof is same for the string "0.0" and for some
>invalid input "Invalid". Can any body suggest me the way to differentiate an
>invalid float number string and a 0.0.[/color]

Instead of atof use strtod.

Regards
--
Irrwahn Grausewitz (irrwahn33@free net.de)
welcome to clc: http://www.ungerhu.com/jxh/clc.welcome.txt
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[Sreekanth]

Re: atof() failure case

Thanks, But it also returns 0 in both cases.. I want to differentiate an
invalid string and a Zero string in a string to float conversion mechanism.



"Irrwahn Grausewitz" <irrwahn33@free net.de> wrote in message
news:728v70l4a9 729m9gficpg4hkp 267c1rd50@4ax.c om...[color=blue]
> "Sreekanth" <sreekanth@yaho o.com> wrote:[color=green]
> >Hello,
> >Am trying to convert a string to float. Am using atof() for that purpose.
> >But the return value for atof is same for the string "0.0" and for some
> >invalid input "Invalid". Can any body suggest me the way to differentiate[/color][/color]
an[color=blue][color=green]
> >invalid float number string and a 0.0.[/color]
>
> Instead of atof use strtod.
>
> Regards
> --
> Irrwahn Grausewitz (irrwahn33@free net.de)
> welcome to clc: http://www.ungerhu.com/jxh/clc.welcome.txt
> clc faq-list : http://www.faqs.org/faqs/C-faq/faq/
> clc OT guide : http://benpfaff.org/writings/clc/off-topic.html[/color]

[Jens.Toerring@physik.fu-berlin.de]

Re: atof() failure case

Sreekanth <sreekanth@yaho o.com> wrote:[color=blue]
> "Irrwahn Grausewitz" <irrwahn33@free net.de> wrote in message
> news:728v70l4a9 729m9gficpg4hkp 267c1rd50@4ax.c om...[color=green]
>> "Sreekanth" <sreekanth@yaho o.com> wrote:[color=darkred]
>> >Hello,
>> >Am trying to convert a string to float. Am using atof() for that purpose.
>> >But the return value for atof is same for the string "0.0" and for some
>> >invalid input "Invalid". Can any body suggest me the way to differentiate[/color][/color]
> an[color=green][color=darkred]
>> >invalid float number string and a 0.0.[/color]
>>
>> Instead of atof use strtod.
>>[/color][/color]
[color=blue]
> Thanks, But it also returns 0 in both cases.. I want to differentiate an
> invalid string and a Zero string in a string to float conversion mechanism.[/color]

Well, that's why you should use strtod():

double strtod(const char *nptr, char **endptr);

If you got an illegal argument *endptr and nptr are identical after
the call of the function. On legal input what endptr points to is
a pointer to the part of the input string where the conversion
stopped and it differs from nptr.
Regards, Jens
--
\ Jens Thoms Toerring ___ Jens.Toerring@p hysik.fu-berlin.de
\______________ ____________ http://www.toerring.de

[Sreekanth]

Re: atof() failure case

Thanks Gentleman.. Working..

<Jens.Toerring@ physik.fu-berlin.de> wrote in message
news:c5oa33$418 ks$1@uni-berlin.de...[color=blue]
> Sreekanth <sreekanth@yaho o.com> wrote:[color=green]
> > "Irrwahn Grausewitz" <irrwahn33@free net.de> wrote in message
> > news:728v70l4a9 729m9gficpg4hkp 267c1rd50@4ax.c om...[color=darkred]
> >> "Sreekanth" <sreekanth@yaho o.com> wrote:
> >> >Hello,
> >> >Am trying to convert a string to float. Am using atof() for that[/color][/color][/color]
purpose.[color=blue][color=green][color=darkred]
> >> >But the return value for atof is same for the string "0.0" and for[/color][/color][/color]
some[color=blue][color=green][color=darkred]
> >> >invalid input "Invalid". Can any body suggest me the way to[/color][/color][/color]
differentiate[color=blue][color=green]
> > an[color=darkred]
> >> >invalid float number string and a 0.0.
> >>
> >> Instead of atof use strtod.
> >>[/color][/color]
>[color=green]
> > Thanks, But it also returns 0 in both cases.. I want to differentiate an
> > invalid string and a Zero string in a string to float conversion[/color][/color]
mechanism.[color=blue]
>
> Well, that's why you should use strtod():
>
> double strtod(const char *nptr, char **endptr);
>
> If you got an illegal argument *endptr and nptr are identical after
> the call of the function. On legal input what endptr points to is
> a pointer to the part of the input string where the conversion
> stopped and it differs from nptr.
> Regards, Jens
> --
> \ Jens Thoms Toerring ___ Jens.Toerring@p hysik.fu-berlin.de
> \______________ ____________ http://www.toerring.de[/color]

[CBFalconer]

Re: atof() failure case

Sreekanth wrote:[color=blue]
>
> Am trying to convert a string to float. Am using atof() for that
> purpose. But the return value for atof is same for the string "0.0"
> and for some invalid input "Invalid". Can any body suggest me the
> way to differentiate an invalid float number string and a 0.0.[/color]

strtod();

--
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
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[Dan Pop]

Re: atof() failure case

In <c5o94k$2ph$1@n ews.mch.sbs.de> "Sreekanth" <sreekanth@yaho o.com> writes:
[color=blue]
>Thanks, But it also returns 0 in both cases..[/color]

It also provides enough clues to make the disambiguation trivial.
[color=blue]
>I want to differentiate an
>invalid string and a Zero string in a string to float conversion mechanism.[/color]

Either use the clues provided by strtod, or use atof and do some minimal
parsing of the string yourself, when the result of the conversion is 0.

Dan
[color=blue]
>"Irrwahn Grausewitz" <irrwahn33@free net.de> wrote in message
>news:728v70l4a 9729m9gficpg4hk p267c1rd50@4ax. com...[color=green]
>> "Sreekanth" <sreekanth@yaho o.com> wrote:[color=darkred]
>> >Hello,
>> >Am trying to convert a string to float. Am using atof() for that purpose.
>> >But the return value for atof is same for the string "0.0" and for some
>> >invalid input "Invalid". Can any body suggest me the way to differentiate[/color][/color]
>an[color=green][color=darkred]
>> >invalid float number string and a 0.0.[/color]
>>
>> Instead of atof use strtod.[/color][/color]

--
Dan Pop
DESY Zeuthen, RZ group
Email: Dan.Pop@ifh.de