Re: convert from alpha to int

[Kjell Ahlstedt <kjell ahlstedt bredband net>]

Hi,

I don't know of any way that is both good and easy.
atoi() is easy to use, but not very good. Both atoi("2") and 
atoi("2Hello") will be returned as 2.

Better, but not as easy is

char* endp = 0;
long i = strtol(s, &endp, 10);
if (*endp == '\0')
// It's a number.

Not even this is perfect. If you want to accept trailing blanks, you 
have to complicate it further. And I don't know how well it works in a 
totally international program. E.g. I don't know if it accepts Arabic 
digits (٠١٢٣٤٥٦٧٨٩).

Kjell

2012-03-19 08:38, Yann Leydier skrev:
> Hi,
>
> I don't know if Glib has functions to perform such a check, but 
> standard C does:
> http://www.cplusplus.com/reference/clibrary/cctype/
>
> If you know that the string's digital value cannot be 0, then you can 
> also check a non-null return to atoi or atol (in cstdlib).
>
> yann
>
> On 18/03/12 20:49, Arbol One wrote:
> > Thank you for your prompt response.
> >
> > I am sorry, I don't think I explained myself well enough. If the user
> > enters the number 24 in an Gtk::Entry, how can I check if the entry is
> > actually a number and not a character string?
> >
> > thank in advance
> >
> > *From:*Kjell Ahlstedt [mailto:kjell ahlstedt bredband net]
> > *Sent:* Thursday, March 15, 2012 11:12 AM
> > *To:* Arbol One
> > *Cc:* gtkmm-list gnome org
> > *Subject:* Re: convert from alpha to int
> >
> > 2012-03-15 13:53, Arbol One skrev:
> >
> > Does Glibmm provide a way to convert an character value to an integer 
> > value?
> >
> > TIA