use strict; 
 
my $input; 
my %h; 
$h{show} = \&show; 
 
 
while (1>0) 
{ 
	$input = <STDIN>; 
	$h{$input}->(); 
} 
 
sub show() 
{ 
	printf "bla"; 
}

use strict; 
use warnings; 
 
my $input; 
my %h; 
$h{show} = \&show; 
 
while (1) { 
	chomp( $input = <STDIN> ); 
	$h{$input}->(); 
} 
 
sub show() { 
	printf "bla"; 
}

Use of uninitialized value in subroutine entry at temp3.pl line 10, <STDIN> line 1. 
Can't use string ("") as a subroutine ref while "strict refs" in use at temp3.pl line 10, <STDIN> line 1.