Question

My question in Perl is:
Define 2×2 arrays using anonymous lists. Pass the arrays to a subroutine and add them together. Return a reference to sum array and print the values from the main part of the program.

My script is:

#!/usr/bin/perl

use strict;

use warnings;

my @array = ([1,2],[4,5]); 

my $refarray = \@array;

print sumarray($refarray);

sub sumarray

{

 $refarray = shift;

 foreach (@{$refarray})

 {

  $refarray = ($refarray[0]->[0]+$refarray[1]->[0],$refarray[0]->[1]+$refarray[1]->[1]);

 }

 return $refarray;

}

Where am I going wrong? Please help. Thanks in advance.

I am getting the output as 0.

If I use use strict; and use warnings; I will get the error message as

Global symbol "@refarray" requires explicit package name at line 23.
Global symbol "@refarray" requires explicit package name at line 23.
Global symbol "@refarray" requires explicit package name at line 23.
Global symbol "@refarray" requires explicit package name at line 23.
Execution aborted due to compilation errors.

Answer 1

Few problems with your code: –

• First, in your for-loop, you are modifying your reference $refarray which you should not do.
• Second, $refarray[0]->[0] will not compile. Since $refarray is a reference to an array, you should either use its 1st element using arrow: – $refarray->[0][0], or you need to de-reference it before using the way you are using: – $$refarray[0]->[0].

Having said that, I think you should replace your subroutine with this one: –

use strict;
use warnings;

my @array = ([1,2],[4,5]); 
my $refarray = \@array;

my $sum = sumarray($refarray);
print $sum->[0], $sum->[1];

sub sumarray {
    my $ref = shift;
    return [$ref->[0][0] + $ref->[1][0], $ref->[0][1] + $ref->[1][1]];
}

OUTPUT: –

5 7