unless ( open(FILE, $filename) ) {
print "Cannot open file \"$filename\"\n\n";
exit;
}
####
open my $FILE, '<', $filename
or die "Cannot open file '$filename': $!\n";
####
# Sum of all elements in array:
$sum=0;
$sum=eval join '+',@array;
####
# Sum of all elements in array:
$sum=0;
$sum+=$_ for @array;