Arguments By Reference

Modify scalar, hash and list through a subroutine.

#!/usr/bin/perl -w
use strict;

my $name;
my %contacts;
my @children;

&my_function(\$name, \%contacts, \@children);


print "Name = $name\n";

foreach my $key ( keys(%contacts) ) {
    print "$key = $contacts{$key}\n";
}
 
foreach my $child (@children) {
    print "Child = $child\n";
}

sub my_function() {
    my $ref_name      = $_[0];
    my $ref_contacts  = $_[1];
    my $ref_children  = $_[2];
    
    $$ref_name = "Harry";
    $$ref_contacts{'home'} = '1234567890';
    $ref_contacts->{'work'} = '9876543210';

    push(@$ref_children, 'James');
    push(@$ref_children, 'Mary');

    print "Name = $$ref_name\n";
    
    foreach my $key ( keys(%$ref_contacts) ) {
        print "$key = $$ref_contacts{$key}\n";
    }
    
    foreach my $child (@$ref_children) {
        print "Child = $child\n";
    }
    print "\n";       
}