use strict;
foreach (0 .. 10) {
  my $foo;
  $foo = 0 unless $_;
  print $foo++, ' ';
}

0 0 0 0 0 0 0 0 0 0 0

use strict;
foreach (0 .. 10) {
  my $foo = 0 unless $_;
  print $foo++, ' ';
}

0 0 1 2 3 4 5 6 7 8 9

use strict;
foreach (0 .. 10) {
  my $foo = 0 unless $_;
  print $foo, ' ';
  $foo++
}

0  1 2 3 4 5 6 7 8 9