#!/usr/local/bin/perl
use warnings;
 
 my $key;
 my $dispatch;


  my %dispatch = (
     "foo" =>  sub {
  my $x = 3;
  my $ans = ($x**2);

  print "answer is: $ans \n"; #prints "answer is: 9"

  },
 "moo" =>  sub {
  my @data = (3,7,15,28);
  my $radius;
  my $radius_ref = @data;
  foreach  $radius(@$radius_ref) {

  print "my radius is: $radius \n";

   my $area = 3.14159 * ( $radius ** 2);
   print "and circle area is $area \n";
    }

 }
 );

 #Perl PCB 5.2 reference
 my $input;
 foreach $input("foo", "moo"){ 
 if ( exists ${dispatch}{ $input } ) {
      ${dispatch} {$input}(  );
  print "$input is the answer.\n";
 }
 else {
     die "Cannot find the subroutine $input\n";
 }

 }