#!/usr/bin/perl -w

use 5.034;

my $rate = 0.21;

unless ($ARGV[0]){
    say "Usage: $0 <1234.56>";
    say "";
    say "This program output the amount of implicit price";
    say "corresponding to a determined final price after VAT.";
    exit 1;
}

# The maths are simple:
# imp_price * (1+VAT) = final_price 
# so imp_price = final_price / (1+VAT)

say "Implicit price = ", sprintf ("%.02f", ($ARGV[0]/(1+$rate))), "";
say "         VAT   = ", sprintf ("%.02f", ($ARGV[0]*$rate/(1+$rate))), "";

exit 3;