dereferencing array in a subroutine

Ratna_Ranjan has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks

I want to pass an array into a subroutine and dereference it and print it in a particular format.Below is the code that I tried.

But the error i get is Gobal symbol "$sample" requires explicit package name at deref.pl line 9.

can someone plz explain me what is wrong in my code??and how to dereference the array and print the array elements with a tab between them??

#!/usr/bin/perl 
use strict;

my @sample=qw(a,b,c);
&trial(\@sample);
sub trial
{
   @sample=@_;
   print join("\t",@$sample);
}
[download]

Comment on dereferencing array in a subroutine Download Code

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Re: dereferencing array in a subroutine by toolic (Bishop) on Oct 28, 2009 at 17:56 UTC
Here is an annotated version of your code to try and demonstrate the issue: `#!/usr/bin/perl use strict; # Great start! my @sample=qw(a,b,c); # Declare array variable &trial(\@sample); # Pass array as a reference to sub sub trial { @sample=@_; # Clobber the contents of your origina +l array # setting the original array to the co +ntents # of the special array (@_), which jus +t has # a reference print join("\t",@$sample); # Try to dereference a scalar variable + named # 'sample', which you never declared. }` [download] use strict and warnings... warnings would also show another issue with your use of qw. Here is an improved version: `#!/usr/bin/perl use strict; use warnings; my @sample = qw(a b c); trial(\@sample); sub trial { my ($aref) = @_; print join "\t", @{ $aref }; }` [download] See also References quick reference	[reply] [d/l] [select]
Re: dereferencing array in a subroutine by almut (Canon) on Oct 28, 2009 at 17:46 UTC
`... my @sample=qw(a b c); trial(\@sample); sub trial { my ($sample) = @_; print join("\t",@$sample); }` [download] This would assign the array reference passed to the routine to the reference `$sample` (a local lexical scalar variable), which you can then dereference to an array using `@$sample`.	[reply] [d/l] [select]