Passing string and hash ref to subroutines - perl

Question

I am passing a string and a hash to a subroutine where the hash is accepted as a reference to the subroutine. At the end of the subroutine call, I expect my hash to be filled. Snapshot:
#!/usr/local/bin/perl5.8
sub passHashAndFile {
my ($file, $hashRef) = #_;
open(HANDLE, $file) or die("Can not open file $file \n");
while(<HANDLE>) {
my #splitted_values = split("--", $_);
$hashRef->{$spllited_values[0]} = $hashRef->{$spllited_values[1]};
}
close(HANDLE);
}
my %hash;
passHashAndFile("test.txt", %hash);
foreach my $elem (keys %hash) {
print "Key = $elem, Value = $hash{$elem}\n";
}
And my test.txt looks like this:
1--2
3--4
5--6
7--8
I am catching hash as an reference and then dereferencing it to fill the values. What wrong did it do?

Answer 1

passHashAndFile("test.txt", %hash);
should be
passHashAndFile("test.txt", \%hash);
Additionally, you have misspelled variable names, you assigning the wrong value, you're using unlocalized global vars, and you're using problematic 2-arg open. Also, most people would have the sub return a hash ref instead of taking a ref to an empty hash.
#!/usr/local/bin/perl5.8
use strict;
use warnings;
sub parse_file {
my ($qfn) = #_;
open(my $fh, '<', $qfn)
or die("Can't open file \"$qfn\": $!\n");
my %hash;
while (my $line = <$fh>) {
my ($key, $val) = split(/--/, $line);
$hash{$key} = $val;
}
return \%hash;
}
my $hash = parse_file("test.txt");
for my $key (keys %$hash) {
print "Key = $key, Value = $hash->{$key}\n";
}
We usually leave out of our answers, but always use use strict; use warnings;. It would have found at least one of the problems.