CS 368-1 (2011 Summer) — Day 8 Script

Below is the little floating-point comparison script I ran in class.

#!/usr/bin/perl

use strict;
use warnings;

my $n = 0;
for (my $i = 0; $i < 10; $i++) { $n += 0.1; }

print "\$n = $n\n";

if ($n == 1.0) {
    print "\$n == 1.0\n";
} else {
    print "\$n != 1.0\n";
}

if ($n < 1.0) {
    print "\$n < 1.0\n";
} else {
    print "\$n !< 1.0\n";
}

if (fp_equal($n, 1.0, 10)) {
    print "\$n fp== 1.0\n";
} else {
    print "\$n fp!= 1.0\n";
}

sub fp_equal {
    my ($left, $right, $precision) = @_;
    return sprintf("%.${precision}g", $left) eq sprintf("%.${precision}g", $right);
}