my @vars = (7, 12, 49, 44);
sub bubble_sort {
   for my $i (1 .. $#vars) {
      for my $j (0 .. $i-1) {
         print "vars[$i]=$vars[i], vars[$j]=$vars[j]: ";
         if ($vars[i]<$vars[j]) {
            print "vars[$i]<vars[$j], swapping!\n";
            my $t=$vars[i]; $vars[$i]=$vars[$j]; $vars[$j]=$t;
         }
         else {
            print "vars[$i]>=vars[$j], no swap needed.\n";
         }
      }
   }
}