#!/usr/bin/perl

use warnings;
use strict;

my $productRef = sub
{
   my $product = 1;

   foreach ( @_ ) {
      $product *= $_;
   }

   return $product;
};

my $printVal = &$productRef( 1, 2, 3, 4 );
print( join( ' * ', 1, 2, 3, 4  ), " = " );
print( "$printVal\n" );