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From: asaph@TAURUS.BITNET
Newsgroups: comp.sys.amiga
Subject: Re:Random Number Generation
Message-ID: <1168@taurus.BITNET>
Date: 6 Jan 90 23:27:04 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: <asaph%math.tau.ac.il@CUNYVM.CUNY.EDU>
Organization: Tel-Aviv Univesity Math and CS school, Israel
Lines: 51

In article <15579@haddock.ima.isc.com> bryanc@haddock.ima.isc.com (Bryan Cote) w
>
>Simply, does anyone have any suggestions on the best way to generate random
>values on the amiga? I am using a public domaine c compiler and have yet
>to find a library call to generate random numbers. I've been reading this
>newsgroup on and off for a year or so but don't recall seeing this discussed.
>Any help will be greatly appreciated, thanks!
>
>------------------------------------------------------------------------------

The following program uses a random number generator described in
communications of the ACM. It is considered a good one. If anyone
is interested I might be persuaded to look up the exact issue and
author.

#define ARAND   16807
#define MRAND   2147483647
#define QRAND   127773
#define RRAND   2836

long RandomSeed;

long Random()
{
  long lo,hi,test;
  hi = RandomSeed/QRAND;
  lo = RandomSeed%QRAND;
  test = ARAND*lo + RRAND*hi;
  if (test>0) RandomSeed = test;
  else RandomSeed=test+MRAND;
  return(RandomSeed);
}

main(argc,argv)
int argc;
char *argv[];
{
  int l;
  long r;
  if (argc != 2) printf("usage: rand <seed>\n");
  else {
    RandomSeed = atol(argv[1]);
    for (l=0; l<500; l++) {
      r = Random();
      printf("%d) %ld %ld\n",l,r,r%2);
    }
  }
}

                                                Asaph
asaph@taurus.bitnet                             asaph@math.tau.ac.il