#!/usr/bin/perl -w
#
# histogram:
# Generate simple histogram by binning data.
#
# Copyright (c) 2001 Chris Lightfoot. All rights reserved.
#

my $rcsid = '$Id: histogram,v 1.1 2001/06/11 20:52:23 chris Exp $';

$binsize = $ARGV[0];
$binsize ||= 5;

$total = 0;

while ($_ = <STDIN>) {
    chomp;
    ++$bin[int($_/$binsize)];
    ++$total;
}

$integ = 0;
$mean = 0;

for ($i = 0; $i <= $#bin; ++$i) {
    $bin[$i] ||= 0;
    $bin[$i] /= $total * $binsize;
    $integ += $binsize * $bin[$i];
    $mean += ($i * $binsize + $binsize / 2) * $bin[$i] * $binsize;
    print STDOUT ($i * $binsize + $binsize / 2) . " $bin[$i] $integ\n";
}

print STDERR "mean = $mean\n";