my $file = 'C:/ppp.txt';
print "file '$file' ";
if (-e $file) {
	print 'exists ';
	if (-z $file) {
		 # print 'but is empty';
		 my $fh, '>>', $file, or die "Could not open file '$file' for appending: $!";
                 print$fh $address . ' or whatever you want';
                 close $fh;
	} else {
		 # print 'and is not empty';
                 ... (your "old" open and while loop)
	}
} else {
	# print q!doesn't exist!;
        ... (either create it or print error message)
}
print "\n";