print "With Hash:\n\n";

$save = tell DATA;

while(<DATA>) {
     my ($k, $v) = split '\|';
     $hash{$k} = $v;
}
print "$_|$hash{$_}" for sort { $a <=> $b } keys %hash;

seek DATA, $save, 0;

print "\n\nWith array:\n\n";
while(<DATA>) {
     my ($k, $v) = split '\|';
     push @arr, [$k, $v];
}
print "$_->[0]|$_->[1]" for sort { $a->[0] <=> $b->[0] } @arr;

__DATA__
30|microsoft
70|aol
76|netscape
5|trouble?
35|mozilla
30|die microsoft
40|opera
100|FireFox
5|no more trouble