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Re: maximum value of int

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On 09/17/11 05:07 PM, Stanley Rice wrote:
> Hello all
>
> I don't know it is appropriate to post such a short or easy question
> here. I couldn't understand some line of code abot maximum int value
> as below:
>
>      #define INT_MAX (((unsigned)-1)>>  1)
>
> The first time I saw it, I was confused why it could pass the
> examination of the compiler. I try to make a bit modification, say
>      #define INT_TEST ((unsigned) - 1)
> This time, the compiler also shuts its mouth, but when I try
>      #define INT_TEST (unsigned)
> The compiler begins to shout to me.
>
> I'm confused about why the type itself, i.e unsigned, could do
> subtration. And it could generate an integer. But when I leave the
> type alone, the compiler tries to stop me.

(unsigned)-1 is a cast, not a subtraction.

-- 
Ian Collins

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maximum value of int Stanley Rice <heconghui@gmail.com> - 2011-09-16 22:07 -0700
  Re: maximum value of int Ian Collins <ian-news@hotmail.com> - 2011-09-17 17:25 +1200
    Re: maximum value of int Stanley Rice <heconghui@gmail.com> - 2011-09-17 00:47 -0700
      Re: maximum value of int Paul N <gw7rib@aol.com> - 2011-09-17 03:53 -0700
      Re: maximum value of int Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-17 12:17 +0100
      Re: maximum value of int Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2011-09-17 10:31 -0600
        Re: maximum value of int Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-09-17 19:51 +0100
      Re: maximum value of int Keith Thompson <kst-u@mib.org> - 2011-09-17 14:39 -0700
  Re: maximum value of int Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-17 07:51 -0400

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