PL/SQL :: To Create A Procedure Which Have 3 Parameters

I would like to create a procedure which have 3 parameters. suppose in Date_birth, in Dept , out number_of_records

if i pass null value to one of the parameter it should return all values . if a pass value to the parameter it should return as per parameter values

Create or replace Procedure Emp_Test (P_dop in Date,P_Dept in number , P_noof_records out Number,
p_recordset Out Sys_Refcursor) as
Begin
OPEN p_recordset FOR
Select Emp_cd,Emp_name, Date_of_Birth,Dept,Count(emp_Cd) noof_records
From Emp_Master Where Date_of_birth =P_date_of_Birth
and Dept=P_dept ;
End ;