Re: obj 8-2 topic

Marek Novotny <(E-Mail Removed)> writes:
> #!/usr/bin/perl
> # File: obj8-2.pl
> # Use loops and if statements to find the greatest number in the array.
> # Once you determine this number be sure to print it out.
> # Use comments to explain every line of your code:
>
> @array = (42,41,42,31,54,42,56,57,46,58,59,60,34,61);
>
> $a = 0;
> $b = 1;
> $i = 0;
>
> while ($i < ($#array * 2)){
> if (($array[$a]) >= ($array[$b])){
> $c = ($array[$a]);
> $b++;
> }else{
> if (($array[$b]) >= ($array[$a])){
> $c = ($array[$b]);
> $a++;
> }
> }
> $i++;
> }
> print "The Answer is: $c\n";

Additional remark: This is broken, cf

--------------
@array = (-1, -2);

$a = 0;
$b = 1;
$i = 0;

while ($i < ($#array * 2)){
print("$c\n");

if (($array[$a]) >= ($array[$b])){
$c = ($array[$a]);
$b++;
}else{
if (($array[$b]) >= ($array[$a])){
$c = ($array[$b]);
$a++;
}
}
$i++;
}
print "The Answer is: $c\n";
------------------

What happens here is that $b runs over the end of the array and the
value of elements of @array beyond $array[1] is undef. That's no problem
if all real elements have values >= 0 because undef is equivalent to 0
when used in a numerical operation. But if the largest value in the
array is smaller than 0, undef will compare greater.