use strict;
use warnings;

$undeclaredVar = 0; # strict gets grumpy about this because the variable isn't declared

my $globalVar = 0; # This variable can be used by any following part of the code

for my $loopVar (1 .. 10) {
    # In the scope of the for loop. $loopVar can only be used within this loop
    # Loop variables are somewhat magical
    
    my $localVar = $loopVar * 3; # This variable is also local to the loop. It
        # is a different variable each time through the loop!
    my $globalVar = $localVar;   # Bad! This $globalVar hides the $globalVar
        # declared outside the loop. Reusing variable names like this is very
        # bad style!
        
    if ($localVar == 9) {
        my $nestedVar = rand(10); # This variable is only available inside this
            # if block. It's not available in the else part or after the if
    } else {
        my $nestedVar = rand($localVar); # Reusing the name here is ok, but note
            # that this is a different variable than the $nestedVar in the if
            # block. Note that we can use variables from the encompassing
            # scope in a nested scope.
    }
    
    my @trailingVar; # This array variable isn't available to any earlier part
        # of the program. In general declare variables in as small a scope as
        # you can and initialize them to the first value they should have.
        # Arrays and hashes are created empty so they don't generally need an
        # explicit initial value.
}

my @anotherGlobal = ('Hello', 'World'); # This global array variable isn't
    # available to the loop code above because it's declared after the loop.
    # Note that we can initialize an array variable using a list