--package creation
create or replace package demopackage as
function get_random (p_start number,p_end number)
return number;
function is_even(p_number number) return boolean;
procedure insert_num(p_num1 number,p_num2 number);
end demopackage;


create of replace package body  demopackage as

function get_random(p_start number,p_end number) return number
as l_num number;
begin
l_num :=dbms_random.value(p_start number,p_end number);
return l_num;
end get_random;

function is_even(p_num number) return boolean as
begin
if (mod(p_num,2)=0) then 
return true;
else
return false;
end if;
end is_even;

--function insert_num()
procedure insert_num(p_num1 number, p_num2 number)
as my_num number;
begin
my_num :=get_random(p_num1 ,p_num2);
if (is_even(my_num)) then 
insert into even_tab values(my_num);
else
insert into odd_tab values(my_num);
end if;
--commit;
end insert_num;
end demopackage;

SCOTT@orcl> -- tables needed for package body creation:
SCOTT@orcl> create table even_tab (my_num  number)
  2  /

Table created.

SCOTT@orcl> create table odd_tab (my_num  number)
  2  /

Table created.

SCOTT@orcl> -- creation of package specification:
SCOTT@orcl> create or replace package demopackage as
  2    function get_random (p_start number, p_end number) return number;
  3    function is_even (p_number number) return boolean;
  4    procedure insert_num (p_num1 number, p_num2 number);
  5  end demopackage;
  6  /

Package created.

SCOTT@orcl> show errors
No errors.
SCOTT@orcl> -- creation of package body:
SCOTT@orcl> -- create of replace package body demopackage as
SCOTT@orcl> -- create OR replace, as below, not create OF replace as above:
SCOTT@orcl>   create or replace package body demopackage as
  2    function get_random (p_start number, p_end number) return number as
  3  	 l_num number;
  4    begin
  5  --    l_num := dbms_random.value (p_start number, p_end number);
  6  -- there should not be any data type parameters when you call a function, as above, should be as below:
  7  	 l_num := dbms_random.value (p_start, p_end);
  8  	 return l_num;
  9    end get_random;
 10  
 11  --  function is_even (p_num number) return boolean as
 12  -- parameter names in package specification and package body must match;
 13  -- it was p_number in the package specification, not p_num as above, so it must be p_number in the package body as below:
 14    function is_even (p_number number) return boolean as
 15    begin
 16  --    if (mod (p_num, 2) = 0) then return true;
 17  -- again the parameter name must match, so it needs to be p_number as below, not p_num as above:
 18  	 if mod (p_number, 2) = 0 then return true;
 19  	 else return false;
 20  	 end if;
 21    end is_even;
 22  
 23    procedure insert_num (p_num1 number, p_num2 number) as
 24  	 my_num number;
 25    begin
 26  --    my_num := get_random (p_num1 ,p_num2);
 27  -- need to round or truncate or something if you want whole numbers:
 28  	 my_num := round (get_random (p_num1, p_num2));
 29  	 if (is_even(my_num)) then insert into even_tab values(my_num);
 30  	 else insert into odd_tab values(my_num);
 31  	 end if;
 32    end insert_num;
 33  end demopackage;
 34  /

Package body created.

SCOTT@orcl> show errors
No errors.
SCOTT@orcl> -- test execution:
SCOTT@orcl> exec demopackage.insert_num (1, 20)

PL/SQL procedure successfully completed.

SCOTT@orcl> exec demopackage.insert_num (1, 20)

PL/SQL procedure successfully completed.

SCOTT@orcl> exec demopackage.insert_num (1, 20)

PL/SQL procedure successfully completed.

SCOTT@orcl> exec demopackage.insert_num (1, 20)

PL/SQL procedure successfully completed.

SCOTT@orcl> select * from even_tab
  2  /

    MY_NUM
----------
        16
         8

2 rows selected.

SCOTT@orcl> select * from odd_tab
  2  /

    MY_NUM
----------
         3
         5

2 rows selected.

CREATE OR REPLACE PROCEDURE fix_code
  (p_name  IN VARCHAR2,
   p_old   IN VARCHAR2,
   p_new   IN VARCHAR2)
AS
BEGIN
  FOR r IN
    (SELECT LISTAGG (text, ' ') WITHIN GROUP (ORDER BY line) || CHR(10) || '/' code
     FROM   user_source
     WHERE  name LIKE p_name
     GROUP  BY name)
  LOOP
    DBMS_OUTPUT.PUT_LINE ('CREATE OR REPLACE ' || REPLACE (r.code, p_old, p_new));
  END LOOP;
END fix_code;
/

STORE SET saved_settings REPLACE
SET ECHO OFF FEEDBACK OFF HEADING OFF PAGESIZE 0 VERIFY OFF
spool fix_code.sql
EXEC fix_code ('DO%', 'this', 'that')
spool off
START saved_settings