# In your subroutines, you can access the value of any global variable.
# A global variable is a variable that is accessible across the entire Perl script. 
        
# A subroutine can use data set up by other parts of your Perl scripts:

#!/usr/bin/perl -w

# Accessing global variables in subroutines.
$a = 1;
$b = 4;

$value = add();

print "$a plus $b is $value.\n";

sub add {
    return ($a + $b);
}

# sub3.pl