A => A 6.8888
B => B  6.8888
C => C 6.8888
D => D 6.8888

##</code><code>##

my @letters=qw(A B C D);
print '    ';
    foreach my $key (@letters){          
        printf ("%s", $key);
    }
    
    "\n";
    
    foreach my $key (@letters) {
        print $key,' ';
        foreach my $key2 (@letters) {
            printf ("%.1f" , $A->{$key}->{$key2});
        }
        print "\n";
    }
}


##</code><code>##


      A      B      C      D
A    6.8    0.1    0.1    0.1 
B    0.1    6.8    0.1    0.1    
C    0.1    0.1    6.8    0.1
D    0.1    0.1    0.1    6.8