#!/usr/bin/perl
use CGI;
my $q = new CGI;
my $summ = 100;
my $peritem = 1;
print "Content-type: text/html\n\n";
unless ($q->param('buyit')) {
print "You have $summ coins.
All items cost $peritem coin.";
} else {
my $num = int($q->param('items'));
my $cost = sprintf("%.2f", $num * $peritem);
print "You try to buy $num items, for $cost coins.
";
if ($cost > $summ) {
print "You have not enough money
";
} elsif ($cost < 0) {
print "Invalid number
";
} else {
$summ-=$cost;
print "You buy $num items for $cost coins. You have $summ coins left
";
}
}
####
** 23 coins:
You try to buy 23 items, for 23.00 coins.
You buy 23 items for 23.00 coins. You have 77 coins left
** 102 coins:
You try to buy 102 items, for 102.00 coins.
You have not enough money
** -3 coins:
You try to buy -3 items, for -3.00 coins.
Invalid number
** nan coins:
You try to buy nan items, for nan coins.
You buy nan items for nan coins. You have nan coins left