Newsgroups: comp.std.c
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: subtraction between unsigned ints
Message-ID: <1989Sep6.153407.18638@utzoo.uucp>
Organization: U of Toronto Zoology
References: 
Date: Wed, 6 Sep 89 15:34:07 GMT

In article  kuro@shochu.Sun.Com (Teruhiko Kurosaka - Sun Intercon) writes:
>Does pANSI defines the datatype of the result of subtraction
>between unsigned integers?  Would it be also unsigned?  Then
>what would be the result of subtraction of a number from a
>smaller number? ...

Unsigned - unsigned gives unsigned.  Unsigned arithmetic is done modulo the
type size, roughly speaking, so carries and borrows off the top end are
ignored.  The value of "(unsigned)3 - (unsigned)5" depends on how big the
unsigned type is, but on a 16-bit machine it's probably (unsigned)65534.
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