72:## given a number, performs one iteration of the kaprekar routine and returns num
73:sub gotoNext {
74:    my $n = shift;
75:    my $new_num = sortHiLow($n) - sortLowHi($n); 
76:    while (length $new_num < $digits) 
77:        {$new_num = ("0" . "$new_num")}
78:        
79:    return $new_num;
80:}