G'day virudinesh,

Perhaps you could clarify your intent or, at least, the rationale behind what you want. Currently, you're doing this:

$ perl -Mstrict -Mwarnings -E '
    my %a=();

    $a{1}{"a"}{"A"}="FIRST";
    $a{1}{"c"}{"B"}="THIRD";
    $a{1}{"b"}{"C"}="SECOND";

    foreach my $k1 ( sort keys %a ) {
      foreach my $k2 ( sort keys %{$a{$k1}} ) {
        foreach my $k3 ( sort keys %{$a{$k1}{$k2}} ) {
         print "$a{$k1}{$k2}{$k3}\n";
        }
        
      }
    }
'
FIRST
SECOND
THIRD
[download]

Did you perhaps want something like this:

$ perl -Mstrict -Mwarnings -E '
    my @items_to_print_outside_loop;
    my %a=();

    $a{1}{"a"}{"A"}="FIRST";
    $a{1}{"c"}{"B"}="THIRD";
    $a{1}{"b"}{"C"}="SECOND";

    foreach my $k1 ( sort keys %a ) {
      foreach my $k2 ( sort keys %{$a{$k1}} ) {
        foreach my $k3 ( sort keys %{$a{$k1}{$k2}} ) {
         push @items_to_print_outside_loop, "$a{$k1}{$k2}{$k3}";
        }
        
      }
    }

    print join("\n", @items_to_print_outside_loop), "\n";
'
FIRST
SECOND
THIRD
[download]

or like this:

$ perl -Mstrict -Mwarnings -E '
    sub print_outside_loop { print "@_\n" }
    my %a=();

    $a{1}{"a"}{"A"}="FIRST";
    $a{1}{"c"}{"B"}="THIRD";
    $a{1}{"b"}{"C"}="SECOND";

    foreach my $k1 ( sort keys %a ) {
      foreach my $k2 ( sort keys %{$a{$k1}} ) {
        foreach my $k3 ( sort keys %{$a{$k1}{$k2}} ) {
         print_outside_loop($a{$k1}{$k2}{$k3});
        }
        
      }
    }
'
FIRST
SECOND
THIRD
[download]

Update: removed -Mdiagnostics (3 instances). A cut-and-paste error which got accidentally propagated. It doesn't hurt but it's not needed and might be confusing with respect to the reason for its inclusion. (Oops! Update of update: s/It does hurt/It doesn't hurt/)