1. you should try to get this working with -w/strict
2. you seem to have some "carry" problems...

   $a = '99999999999999999999999999999999999';
   $b = '1';
   print "  $a\n+ $b\n= ", add($a, $b);
   [download]

   Gives...

     99999999999999999999999999999999999
   + 1
   = 00000000000000000000000000000000000
   [download]

The problem doesn't seem to be the -w, but rather that $In_Mente is forgotten. -w is always complaining about uninitialized-whatsoever, so we'll just have to make some precautions:



sub add($$) {
    my ($Val1, $Val2) = @_;
    my ($Result, $Tmp) = ('',0);
    my $In_Mente = '';
    (length($Val1) < length($Val2)) ? ($Val1, $Val2)=($Val2, $Val1):0;
    while (length($Val2) || length($Val1)) {
        $Tmp = substr($Val1,-1,1);
    $Tmp += substr($Val2, -1, 1) if (length($Val2));
    $Tmp += $In_Mente if (length($In_Mente));
        if ($Tmp > 9) { $In_Mente = 1; $Tmp -= 10;}
        else { $In_Mente = ''; }
        $Result = $Tmp . $Result;
        substr($Val1, -1, 1) = '';
        substr($Val2, -1, 1) = '';
        my $FResult = $Result;
        last if ($In_Mente eq '' && !length($Val2));
        }
    $Result = $In_Mente . $Result;
    $Result = $Val1 . $Result;
    return $Result;
    }

$a = '99999999999999999999999999999999999999999999';
$b = '1';
print "  $a\n+ $b\n= ", add($a, $b);
[download]


Prints out:


  99999999999999999999999999999999999999999999
+ 1
= 100000000000000000000000000000000000000000000
[download]

Here is my try. It adds numbers, but is not limited to two arguments. It's recursive and probably not very efficient. (Anyone want to benchmark the two solutions?)

sub add {
    my $current = 0;
    return '' unless @_ = grep length, @_;
    $current += substr $_, -1, 1, '' for @_;
    push @_, substr $current, 0, -1, '' if length $current > 1;
    return &add . $current;
}
[download]

$\ = "\n";

print add(
    '999999999999999999999997',
                           '1',
                           '2'
);

print add(
    '9999999999',
    '9999999999',
     '999999999',
           '999',
             '9'
);

# Next line is not -w safe: "Deep recursion"... grin.
print add('9' x 5000, 1) eq '1' . ('0' x 5000) ? "Works" : "Doesn't wo
+rk";
[download]

- Yes, I reinvent wheels.
- Spam: Visit eurotraQ.

Now, our big mission in life must be to construct a similar function, that does not add, but substracts...*LOL*


#!s #!s, oh baby when she moves, she moves...