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

my $wheel = 26.5;
my @chainWheels = qw (42 32 22);
my @cogs =  qw (11 13 15 17 19 21 24 28 32);

print "Wheelsize:   $wheel\n"; 
print "Chainwheels: @chainWheels\n";
print "Sprockets:   @cogs\n\n";

for my $chainSel (1 .. @chainWheels) {
    my $wheelMul = $wheel * $chainWheels[$chainSel - 1];

    print "Chain wheel: $chainSel ratios:  \n";

    for my $cogSel (1 .. @cogs) {
        printf "%d: %5.2f ", $cogSel, $wheelMul / $cogs[$cogSel - 1];
    }
    
    print "\n";
}