Local and Global variables in perl

Question

I am having few doubts about the local/our scope in Perl. I read a lot of documentation, but I am still in confusion is there. Following are the confusions

Answer 1

Example 1:

sub mess_with_foo {
      $foo=0;
 }

 sub myfunc {
      my $foo=20;
      mess_with_foo();
      print $foo;
 }
 myfunc();

Example 2:

 sub mess_with_foo {
      $foo=0;
 }

 sub myfunc {
      local $foo=20;
      mess_with_foo();
      print $foo;
 }
 myfunc();

Example 1 prints 20 because mess_with_foo() could not see my $foo. It could not change it. my $foo can only be seen in its scope of myfunc().

Example 2 prints 0 because mess_with_foo() can see my $foo and change it. local $foo can be seen in its scope of myfunc() AND in the scope of any function called from within its scope of myfunc().

That's the only difference. Neither my $foo nor local $foo will be seen outside of their scope of myfunc().