oracle - What is wrong with this PL/SQL? Bind Variable * is NOT DECLARED

Question

Here is:

declare
  v_str1   varchar2(80);
begin
  v_str1 := 'test';
  print :v_str1;
end

When I run it using SQLDeveloper just in a sql worksheet I get this:

Bind Variable "v_str1" is NOT DECLARED
anonymous block completed

Answer 1

Got it:

set serveroutput on

declare
  v_str1   varchar2(80);    
begin
 v_str1 := 'test';
 dbms_output.put_line(v_str1);
end;

More info here.