Groups > comp.os.linux.development.apps > #444

cast double to short problem

From	Bill M <wpmccormick@just_about_everywhere.com>
Newsgroups	comp.os.linux.development.apps
Subject	cast double to short problem
Date	2012-03-06 16:52 -0600
Organization	A noiseless patient Spider
Message-ID	<jj64g2$fb8$1@dont-email.me> (permalink)

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I'm having a loss of precision problem when casting from a double to a 
short.

In the following, for dval = 0.3 ...

short sval = (short)(dval * 10);

... sval = 2. But if I convert it like this ...

double nval = dval * 10;
short sval = (short)nval;

... then sval = 3 as I would expect.

Can some gcc expert tell me what is happening here?

I'm not using any special options to gcc, but maybe that could be an issue?

Thanks!!

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cast double to short problem Bill M <wpmccormick@just_about_everywhere.com> - 2012-03-06 16:52 -0600
  Re: cast double to short problem Grant Edwards <invalid@invalid.invalid> - 2012-03-06 23:21 +0000
    Re: cast double to short problem Bill M <wpmccormick@just_about_everywhere.com> - 2012-03-06 17:36 -0600
      Re: cast double to short problem Grant Edwards <invalid@invalid.invalid> - 2012-03-07 00:30 +0000
        Re: cast double to short problem Noob <root@127.0.0.1> - 2012-03-07 11:17 +0100
          Re: cast double to short problem Grant Edwards <invalid@invalid.invalid> - 2012-03-07 15:23 +0000
    Re: cast double to short problem "Ersek, Laszlo" <lacos@caesar.elte.hu> - 2012-03-07 19:33 +0100
      Re: cast double to short problem Grant Edwards <invalid@invalid.invalid> - 2012-03-07 20:13 +0000
        Re: cast double to short problem Bill M <wpmccormick@just_about_everywhere.com> - 2012-03-08 11:45 -0600

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