perl 函数入门

sub sum_of_fred_and_barney{
    print "Hey,you called the sum_of_fred_and_barney subroutine!\n";
    $fred+$barney;
}
$fred  =3;
$barney=4;
$wilma =&sum_of_fred_and_barney;
print "\$wilma is $wilma.\n";
$betty =3*sum_of_fred_and_barney;
print"\$betty is $betty.\n";

结果：

Hey,you called the sum_of_fred_and_barney subroutine!
$wilma is 7.
Hey,you called the sum_of_fred_and_barney subroutine!
$betty is 21.