#! perl -slw
use strict;

sub incOdo {
    my @odo = @_;
    my $wheel = $#odo;

#    until( $wheel < 0 || $odo[ $wheel ] < 9  ) {
    until( $odo[ $wheel ] < 9 || $wheel < 0  ) {
        $odo[ $wheel ] = 0;
        $wheel--;
    }
    if( $wheel < 0 ) {
        return;
    }
    else {
        $odo[ $wheel ]++;
        return @odo;
    }
}

my @odo = (0) x 2;

for( 1 .. 102 ) {
    print join '', @odo = incOdo( @odo );
}


##</code><code>##

1
2
3
...
97
98
99





##</code><code>##

1
2
3
...
98
99

Use of uninitialized value within @odo in numeric lt (<) at C:\test\junk31.pl line 9.

Use of uninitialized value within @odo in numeric lt (<) at C:\test\junk31.pl line 9.