Hi Uday,
please reply to the list.
I'm going to comment on your code.
On Mon, 21 Sep 2015 15:06:49 +0530
Uday Vernekar <vernekaru...@gmail.com> wrote:
> Hi all,
>
> I wrote a simple Perl code to find the factorial of a number.
> Need feed back on the same.please correct me if i have done anything wrong
>
> #!/usr/bin/perl
> use warnings;
> use strict;
It's good that you used string and warnings, but you should have some empty
lines between paragraphs.
> my $fact=1;
You should avoid pre-declaring your variables.
> print("Enter Number:");
This may not get output in time. You need to flush the output - see perldoc
IO::Handle .
> my $num=<STDIN>;
I personally prefer using <ARGV> or <> for short consistently than <STDIN>
which is more limited.
> if($num==0)
> {
> print("factorial of $num=$fact\n");
> }
No need for this special case, and you have some duplicate code.
Furthermore , you should have spaces between the expressions, like:
«
if ($num == 0)
{
print ("The factorial of $num is $fact\n");
}
»
> elsif($num<0)
> {
> print("please enter only positive integers \n");
> }
Your code is missing indentation and furthermore, this note should be outputted
to STDERR or use die or warn.
> else
> {
> for (1..$num)
> {
> $fact*=$_;
> }
It's a good idea not to use $_ as an implicit looping construct because it can
be overrided very easily. Use a lexical variable:
for my $i (1 .. $num)
{
$fact *= $i
}
It will also be a good idea to extract the code calculating the factorial into
its own subroutine, which will accept a number and return the result.
Finally note that Math::BigInt and Math::GMP already provide ->bfac() for
calculating the factorial, so you should use them instead of your own
homebrewed routines.
Regards,
Shlomi Fish
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