#!/usr/bin/perl
#finalproject_1.pl
use strict;

our $p1 = 0;
our $p2 = 0;
our $pT = 10;
our $a = 0.1;
our $b = 0.1;
our $k = 0.005;
our $d2 = 0.5;
our $d1i = 1000;
our $ci = 200;

our @profit; our @price; 
my $profit = &profit();
our $A;
our $B;
our $C;
our $s;

while ($p1 < 10){
	$p1 += .01; $p2 = $p1;
	$A = ($a*($p1-$p2) + $b*($pT-$p1)/(-2));
	$B = ($p1*($a*($p2-$p1) + $b*($pT-$p1)-$k*$d2-$d1i*$k));
	$C = ($d1i - $ci);
	$s = (((-1)*$B + sqrt($B**2 - 4*$A*$C))/(2*$A));
	$profit = &profit();
	push @price, $p1;
	push @profit, $profit;
}

our @alias = @profit;
my $maxprofit = pop @alias;
foreach (@alias){
	$maxprofit = $_ if $maxprofit < $_;
}
our $index = 0;
++$index until $profit[$index] == $maxprofit or $index > $#profit;

print "The largest profit is $maxprofit and is obtained when price is $price[$index] \n";

#Here thar be subroutines

sub profit {
	(($A*$s**3)/3 + ($B*$s**2)/2 + $C);
}