$array can't print anything - perl

Question

This is my program , I want to let user type a matrix line by line and print the while matrix , but I can't see the matrix
The user will type
1 2 3
4 5 6
7 8 9
like this
and I want to let it show
1 2 3
4 5 6
7 8 9
Perl program
$Num = 3;
while($Num > 0 )
{
$Row = <STDIN>;
$Row = chomp($Row);
#Row_array = split(" ",$Row);
push #P_matrix , #Row_array;
#Row_array = ();
$Num = $Num - 1;
}
for($i=0;$i<scalar(#P_matrix);$i++)
{
for($j=0;$j<scalar(#P_matrix[$i]);$j++)
{
printf "$d ",$P_matrix[$i][$j];
}
print "\n";
}
I change the expression => printf "$d ",$P_matrix[$i][$j]; to print $P_matrix[$i][$j]
but still don't work.

Answer 1

To create a multi-dimensional array, you have to use references. Use
push #P_matrix, [ #Row_array ];
to create the desired structure.
Also, chomp does not return the modified string. Simply use
chomp $Row;
to remove a newline from $Row. Moreover, chomp is not needed at all if you split on ' '.
printf uses % as the formatting character, not $.
You can use Data::Dumper to inspect complex data structures. Use strict and warnings to help you avoid common problems. Here is how I would write your program:
#!/usr/bin/perl
use warnings;
use strict;
use Data::Dumper;
my #p_matrix;
push #p_matrix , [ split ' ' ] while <>;
warn Dumper \#p_matrix;
for my $i (0 .. $#p_matrix)
{
for my $j (0 .. $#{ $p_matrix[$i] })
{
printf '%d ', $p_matrix[$i][$j];
}
print "\n";
}

Answer 2

First and foremost please use use strict; use warnings;
Issues in your code:
You have a single dimensional array, but your are trying to access
it like two dimensional array. In order to make 2 dimensional array push the array reference of Row_array in #P_matrix as [#Row_array].
Where is $d defined? declare $d as my $d or our $d if you mean $d as scalar variable.
OR
For using %d, use need sprintf. Please read this.