use strict;
      use warnings;
   
      my $x = 1; my $y = 20; my $looptimes = 10;
      my %NoDups = ();
   
      while( 1 )
      {   my $num = int( 1 + rand( 19 ) );
          if ( exists $NoDups{ $num } ) { next; }
          $NoDups{ $num } = 1;
          if ( keys %NoDups >= $looptimes ) { last; }
      }
   
      foreach my $no ( sort {$a<=>$b} keys %NoDups )
      {   print "$no\n"; }