Is it possible to pass a null Input Oracle parameter to a stored procedure

Question

I have a stored procedure that take 3 inputs and gives 1 output.I'm using Oracle parameter to add all 3 input parameters as follows :
OracleParameter inobj = cmd.Parameters.Add("wid", OracleDbType.Int32,50);
inobj.Direction = ParameterDirection.Input;
inobj.Value = _employeeID;
and added the output parameter as follows:
OracleParameter outobj = _cmd.Parameters.Add("w_first", OracleDbType.Varchar2, 50);
outobj.Direction = ParameterDirection.Output;
On the UI end , the user has a choice to provide 1 input or all inputs or any 2 inputs based on his interest. Stored Proc looks as follows:
SP( inp1 in parameter, inp2 in parameter, inp3 in parameter, output1 out parameter)
If i just get 1 input or 2 inputs from the user, is it fine to query the data for output using same stored procedure or should i have individual stored procedures for each scenario(combination of different inputs)?
Will i get any pl/sql error that says invalid number of arguements?

Answer 1

This means if i have 1 input , i need to have a different method to pass 1 parameter value and other input parameters as null and if there are 2 inputs will need different method to handle. So 5 different methods all together?
What if the stored procedure is as follows ,will its make things easier so that only one method is used for all scenarios?(optional parameters is set default value as null in the stored proc)
Create or Replace
Procedure GetFoo
(cur_z OUT sys_refcursor,
pub_date IN varchar2,
fname IN varchar2 default null,
lname IN varchar2 default null,
phone IN varchar2 default null
IS
BEGIN
---get some data
END;
*actually i can test this but, all the database servers are down today. So, i need to have idea if this thing works before i confirm with someone. Thanks.