use warnings;
use strict;
use Win32::DirSize;

my $f = "d:\\programs";
print "Manual call\n";
dsize($f);

my @file = ("d:\\programs");
print "Loop call\n";
foreach $f (@file) {
    dsize($f);
}

sub dsize {
chomp (my $param = shift(@_)) ;
print ">$param<\n";
#...
}