SQL & PL/SQL :: Difference Between With Parameter And Without Cursor In Pasted Code?

create table eml(num numner(10),email varchar2(100));

begin
for i in 1..20 loop
insert into eml values(i,'email.'||i||'@mmm.com');
end loop;
end;

I just want to know what is the difference between below two pl/sql block, in one block i am passing the p_email_id as paramter to cursor.Both block are working fine and giving the same result.first thing , i want to know how the p_email_id is passing to cursor get_emil_info without paramter.and which is good to use, i mean without paramter or with paramter.

--without paramterised cursor

declare
v_cnt number;
p_email_id number;
TYPE email_tab is TABLE of NUMBER index by binary_integer ;
eml_id email_tab ;
CURSOR get_eml_id is select num from eml;

[code]...

--with paramterised cursor

declare
p_email_id number;
TYPE email_tab is TABLE of NUMBER index by binary_integer ;
eml_id email_tab ;
CURSOR get_eml_id is select num from eml;

[[code]...