Hi, read this

Tutorials: Debugging and Optimization: Basic debugging checklist

Armed with that knowledge, I modify your program to

 use strict;
use warnings;
use diagnostics;
use 5.01000;

&table( 2, 3, 4 );

sub table {

    my $i = 1;
    my $loop;

    foreach $loop (@_) {
        warn " loop $loop \n";
        for ( $i ; $i <= 10 ; $i++ ) {
            my $ans = $i * $loop;
            print "$ans ";
        }
        print "\n";
    }
}
__END__
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And the output is

 loop 2
2 4 6 8 10 12 14 16 18 20
 loop 3

 loop 4
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So, what is happening is, it is looping over the arguments to the subroutine correctly, but the problem of printing the values, the problem with the inner loop is, the condition is false for some reason

To see why the warn is now

warn " loop $loop i $i \n";
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 loop 2 i 1
2 4 6 8 10 12 14 16 18 20
 loop 3 i 11

 loop 4 i 11
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So  for ( $i ; $i <= 10 ; $i++ ) { first executes  $i; , executed once, on the first run through the loop (loop initialization). It generates this warning Useless use of private variable in void context

Then second part  $i <= 10; checks if 11 is greater than 10, so the loop doesn't execute

Why? Because of scoping, read this

Tutorials: Variable Scoping in Perl: the basics, Coping with Scoping

If you move  my $i = 1; into the inner for loop like  for ( my $i = 1; $i <= 10 ; $i++ ) { it will work as you want

2 4 6 8 10 12 14 16 18 20
3 6 9 12 15 18 21 24 27 30
4 8 12 16 20 24 28 32 36 40
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They call this c-style for loop. The perl-style for loop would be  for my $i ( 1 .. 10 ) {

For learning this level of perlintro I liked http://learn.perl.org/books/beginning-perl/ book, its available as free pdf

Hi, this being your 8th post and all, I've got a link for you :)

PerlMonks FAQ: How do I compose an effective node title?

I recognize that you're very new so it can be real hard to compose a title, but instead of "help me" you might include words you used in the question, words like: loop, sub, parameter, print

Thanks Ansh bhai. I will take care of the title.

1. don't put a & before your subroutine call. Most of the times it is unnecessary, it does things you are clearly not aware of (see perlsub) and unless you know the few cases you need it, just don't do it.
2. You don't need $i (or $ans) at all. Make your inner loop as follows: print $_*$loop, ' ' for 1 .. 10;

#!/usr/local/bin/perl
use strict;
use warnings;
use diagnostics;
use 5.01000;

table( 2, 3, 4 );

sub table {
    foreach my $loop (@_) 
    {
       print $_*$loop, ' ' for 1 .. 10;
       print "\n";
    }
    
}
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