I can't capture the output of a procedure - asp.net

Question

When debugging a function that allows me to create a record, I can't get the output of the procedure. 'Output' never changes its value with which it is initialized ("").
string Agregar(Empleado reg)
{
string mensaje = "";
string output = "";
SqlConnection cn = new SqlConnection(cadena);
try
{
cn.Open();
SqlCommand cmd = new SqlCommand("sp_pregunta02_3 #codEmp,#nom,#ape,#idpais,#email", cn);
cmd.Parameters.AddWithValue("#nom", reg.nomEmployee);
cmd.Parameters.AddWithValue("#ape", reg.apeEmployee);
cmd.Parameters.AddWithValue("#idpais", reg.idpais);
cmd.Parameters.AddWithValue("#email", reg.emailEmployee);
cmd.Parameters.Add("#codEmp", SqlDbType.Int).Direction = ParameterDirection.Output;
cmd.ExecuteNonQuery();
output = cmd.Parameters["#codEmp"].Value.ToString();
mensaje = $"El codigo {output} ya existe";
if (!output.Equals("0"))
mensaje = $"Se ha registro el Empleado de codigo {output}";
}
catch (SqlException ex)
{
mensaje = ex.Message;
}
finally
{
cn.Close();
}
return mensaje;
}
The procedure returns a random employee code from a function that generates random numbers that are not in the table, if it already exists it returns 0.
CREATE OR ALTER PROCEDURE sp_pregunta02_3
#codEmp int OUTPUT,
#nom varchar(255),
#ape varchar(255),
#idpais char(3),
#email varchar(255)
AS
BEGIN
SET #codEmp = dbo.fn_pregunta02();
PRINT #codEmp
IF #codEmp <> 0
BEGIN
INSERT INTO tb_employee
VALUES (#codEmp, #nom, #ape, #idpais, #email)
END
END

Answer 1

Try this code:
SqlCommand cmd = new SqlCommand("sp_pregunta02_3, cn);
cmd.Parameters.Add("#nom", SqlDbType.VarChar).Value = reg.nomEmployee;
cmd.Parameters.Add("#ape", SqlDbType.VarChar).Value = reg.apeEmployee;
cmd.Parameters.Add("#idpais", SqlDbType.Char).Value = reg.idpais;
cmd.Parameters.Add("#email", SqlDbType.VarChar).Value = reg.emailEmployee;
cmd.Parameters.Add("#codEmp", SqlDbType.Int).Direction = ParameterDirection.Output;
cmd.ExecuteNonQuery();
output = cmd.Parameters["#codEmp"].Value.ToString();
In stored procedure you must select the output
CREATE OR ALTER PROCEDURE sp_pregunta02_3
#codEmp int output,
#nom varchar(255),
#ape varchar(255),
#idpais char(3),
#email varchar(255)
as
BEGIN
SET #codEmp = dbo.fn_pregunta02();
PRINT #codEmp
IF #codEmp <> 0
BEGIN
insert into tb_employee
values(#codEmp, #nom, #ape, #idpais, #email)
END
select #codEmp
END