Hello, I want to draw this triangle by perl: 
1
11
121
1331
14641
.......

[download]
and now have some problem with my sub partition, pls see codes below: 
#!/usr/bin/perl

use strict;
use warnings;

my $i;
my $j;
my $k;
my @a;
my @b;

$a[0] = 1;
$a[1] = 1;

for($i=0;$i<=10;$i++){
        @a = &yh(@a);
        print @a,"\n";
}


sub yh{
        my(@a)=@_;
        my @b;
        my $j;
        my $k;

        $k = $#a + 1;

        $b[0] = 1;


        for($i=1;$i<=$k;$i++){
                $j = $i - 1;
                $b[$i] = $a[$i] + $a[$j];
        }
        $b[$k] = 1;
        return @b;
}

[download]
and when run it at command line, 
phillip@Athen:~/script$ perl yanghui.pl
Use of uninitialized value in addition (+) at yanghui.pl line 34.
121
Use of uninitialized value in addition (+) at yanghui.pl line 34.
1331
Use of uninitialized value in addition (+) at yanghui.pl line 34.
14641
Use of uninitialized value in addition (+) at yanghui.pl line 34.
15101051
Use of uninitialized value in addition (+) at yanghui.pl line 34.
1615201561
Use of uninitialized value in addition (+) at yanghui.pl line 34.
172135352171
Use of uninitialized value in addition (+) at yanghui.pl line 34.
18285670562881
Use of uninitialized value in addition (+) at yanghui.pl line 34.
193684126126843691

[download]
I know i can ignore the warning by remove "use strict and use warnings". while my question is ,if i want to remain "use strict" "use warnings" in codes, what can i do to not display this warning message? Thanks, Phillip

In reply to problem in my sub partition by PhillipHuang

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.