#!/usr/bin/env perl
use strict;
use warnings;

use Math::Complex;
use File::Basename;


my $prog = basename($0);
my $USAGE = <<USAGE
Usage: $prog <a> <b> <c>
USAGE
;


sub quad {
    my ($a, $b, $c) = @_;
    my $positive = (
        ($b * -1) - sqrt(($b ** 2) - (4 * ($a * $c))) / (2 * $a)
    );
    my $negative = (
        ($b * -1) + sqrt(($b ** 2) - (4 * ($a * $c))) / (2 * $a)
    );

    return ($positive, $negative);
}

foreach my $arg (@ARGV) {
    if (($arg eq "-h") || ($arg eq "--help")) {
        die $USAGE;
    }
}

my ($a, $b, $c) = @ARGV;
if (!defined $a) {
    print '$a = ';
    $a = <STDIN>;
}
if (!defined $b) {
    print '$b = ';
    $b = <STDIN>;
}
if (!defined $c) {
    print '$c = ';
    $c = <STDIN>;
}

my @result = quad($a, $b, $c);
printf("%s, %s\n", $result[0], $result[1]);


1;
__END__