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From: jsdy@hadron.UUCP (Joseph S. D. Yao)
Newsgroups: net.lang.c,net.micro,net.micro.pc
Subject: Re: weird C behavior
Message-ID: <324@hadron.UUCP>
Date: Sat, 22-Mar-86 04:11:16 EST
Article-I.D.: hadron.324
Posted: Sat Mar 22 04:11:16 1986
Date-Received: Tue, 25-Mar-86 03:23:54 EST
References: <557@utastro.UUCP>
Reply-To: jsdy@hadron.UUCP (Joseph S. D. Yao)
Organization: Hadron, Inc., Fairfax, VA
Lines: 26
Keywords: strange, opaque, odd
Xref: watmath net.lang.c:8240 net.micro:14105 net.micro.pc:7514
Summary: Are you mixing 16 & 32?

In article <557@utastro.UUCP> nather@utastro.UUCP (Ed Nather) writes:
>/* weird.c - demonstrate weird C behavior */
>/* Reference: Kernighan and Ritchie pp. 40-41 */
>#include <stdio.h>
>#define BIG 36864
>main()
>{
>int i;
>
>i = BIG;
>if(i == BIG)
>    printf("Equality found: i = %d, BIG = %d\n", i, BIG);
>else
>    printf("Equality NOT found: i = %d, BIG = %d\n", i, BIG);
>}
>Equality NOT found: i = -28672, BIG = -28672

Check the code produced by your compiler.  Could you be mixing
16- and 32-bit operations?  I.e., could the compiler be moving
the BIG word into 16-bit i (making it a negative number), then
(finding that BIG is > 32767) upgrading both to (long) before
the compare?  Check and see.  You don't say what machine or C
you used, so we have no way of telling.
-- 

	Joe Yao		hadron!jsdy@seismo.{CSS.GOV,ARPA,UUCP}