From:	"John M. Aldrich" <fighteer AT cs DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Testing for float or int
Date:	Thu, 30 Apr 1998 22:54:48 -0400
Organization:	Two pounds of chaos and a pinch of salt.
Lines:	37
Message-ID:	<35493978.6AF8@cs.com>
References:	<35481B84 DOT 167E AT jcu DOT edu DOT au>
NNTP-Posting-Host:	ppp126.cs.net
Mime-Version:	1.0
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Oon Lin wrote:
> 
> I had been surfing around Delorie's lib C online reference for a
> function that can test whether an input is in float or int.

You could always write one yourself that tests for a decimal point in a
numeric value.  I wrote something like it to handle floating point input
fields in a custom-built TUI.  This basically checks each input
character:  if it's numeric it is accepted; if it is non-numeric it is
rejected, and if it's a period it's only accepted if there has not been
a previous period in the same number.

A very simple function might look like this:

int isfloat( const char *str )
{
    for ( ; *str; str++ )
        if ( !isdigit( *str ) )
            if ( *str == '.' )
                return 1;
            else
                return 0;
    return 0;
}

The only true condition is if a sequence of digits leads up to a period;
otherwise the function returns false.

The above code is tested, btw.  :-)

-- 
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|      John M. Aldrich       | "Animals can be driven crazy by pla- |
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|   mailto:fighteer AT cs DOT com   | Homo sapiens is the only animal that |
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