sub print_results {
    if (@_ == 0) {
        print "This data structure is a scalar";
    }
    else {
        if ($_[0] eq 'array') {
            print "This data structure is an array";
        }
        else {
            print "This data structure is a hash";
        }
        shift;
        for (@_) {
            if ($_ eq 'hash') {
                print ' of hashes';
            }
            elsif ($_ eq 'array') {
                print ' of arrays';
            }
        }
    }
    print "!\n";
}