#!/usr/bin/perl

use strict;

require "lib.pl";

my $global_variable1='a';
my $global_variable2='b';
my $global_variable3='c';

switch(&subroutine1){
    case 0: &subroutine2;
    case 1: &subroutine3;
    case 2: &subroutine4;
}


##</code><code>##

#!/usr/bin/perl

use strict;

sub subroutine1 { return rand(3); }
sub subroutine2 { print $global_variable1; }
sub subroutine3 { print $global_variable2; }
sub subroutine4 { print $global_variable3; }