#!/usr/bin/perl -w

use strict;
use warnings 'all';

my (%code, %country, %currency);

while (<DATA>) {
    my $info = [split];
    $code            {$info -> [0]}  =  $info;
    $country         {$info -> [1]}  =  $info;
    push @{$currency {$info -> [2]}} => $info;
}

sub info_by_code {
    my $code = shift;
    $code {$code}
}  

sub info_by_country {
    my $country = shift;
    $country {$country}
}
 
sub info_by_currency {
    my $currency = shift;
    @{$currency {$currency}}
}
 
print "Code for Germany is ", info_by_country ("GER") -> [0], "\n";
print "People pay in Euros in ",
       join (", " => map {$_ -> [1]} info_by_currency ("EUR")), "\n";
 
__END__
US USA USD 
CA CAN CND
DE GER EUR
IT ITA EUR
FR FRA EUR
NL NET EUR
BE BEL EUR
CH SWI SFR
    
    
$ ./countries
Code for Germany is DE
People pay in Euros in GER, ITA, FRA, NET, BEL
$