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From: kevin@math.lsa.umich.edu (Kevin Coombes)
Newsgroups: comp.lang.c
Subject: Re: % operator with negatives
Message-ID: <1990Dec14.153706.14688@math.lsa.umich.edu>
Date: 14 Dec 90 15:37:06 GMT
References: <7461:Dec1310:04:0990@kramden.acf.nyu.edu> <18140@neptune.inf.ethz.ch> <1990Dec14.064305.4491@dirtydog.ima.isc.com>
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Organization: University of Michigan Math Dept., Ann Arbor
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f you know what types you're working with and you're worried about what
happens with negatives, you can always use the following function, which
is guaranteed to return an answer between 0 and p-1.

int
safemod(int a, int p)
{
  if (a < 0)
    return p - ((-a) % p);
  else
    return a % p;
}

Best,
Kevin <krc@mayme.umd.edu>