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]

"Sreekanth" <sr*******@yahoo.com> wrote:

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.

Instead of atof use strtod.

Regards
--
Irrwahn Grausewitz (ir*******@freenet.de)
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[Sreekanth]

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" <ir*******@freenet.de> wrote in message
news:72********************************@4ax.com...

"Sreekanth" <sr*******@yahoo.com> wrote:

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 aninvalid float number string and a 0.0.

Instead of atof use strtod.

Regards
--
Irrwahn Grausewitz (ir*******@freenet.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

[Jens.Toerring]

Sreekanth <sr*******@yahoo.com> wrote:

"Irrwahn Grausewitz" <ir*******@freenet.de> wrote in message
news:72********************************@4ax.com...

"Sreekanth" <sr*******@yahoo.com> wrote:

>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.
Instead of atof use strtod.

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.

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 ___ Je***********@physik.fu-berlin.de
\__________________________ http://www.toerring.de

[Sreekanth]

Thanks Gentleman.. Working..

<Je***********@physik.fu-berlin.de> wrote in message
news:c5************@uni-berlin.de...

Sreekanth <sr*******@yahoo.com> wrote:

"Irrwahn Grausewitz" <ir*******@freenet.de> wrote in message
news:72********************************@4ax.com...

"Sreekanth" <sr*******@yahoo.com> wrote:
>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.

Instead of atof use strtod.

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.
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 ___ Je***********@physik.fu-berlin.de
\__________________________ http://www.toerring.de

[CBFalconer]

Sreekanth wrote:

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.

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.
Q: What is the most annoying thing on usenet and in e-mail?

[Dan Pop]

In <c5**********@news.mch.sbs.de> "Sreekanth" <sr*******@yahoo.com> writes:

Thanks, But it also returns 0 in both cases..
It also provides enough clues to make the disambiguation trivial.
I want to differentiate an
invalid string and a Zero string in a string to float conversion mechanism.
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
"Irrwahn Grausewitz" <ir*******@freenet.de> wrote in message
news:72********************************@4ax.com.. .

"Sreekanth" <sr*******@yahoo.com> wrote:

>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 differentiatean >invalid float number string and a 0.0.

Instead of atof use strtod.

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