procedure_name(a in number,b out varchar)
		(
			script of execution;

		)
		exec procedure_name(first_parameter,second_parameter);

create or replace procedure p_name(p_no in out number)
is begin
{
executable statement
}
end p_name;
/

create or replace procedure <pocedure_name>(x in number,y 
out varchar) is begin
                {
			executable statements;

		}
end <procedure_name>;

exec <procedure_name>(first_parameter,second_parameter);

<procedure_name>(in_parameter_value, 
out_parameter_variable);

create or replace procedure <pocedure_name>(x in number,y 
out number) is begin
                {
			executable statements;

		}
end <procedure_name>;

exec <procedure_name>(10,y);

See the example below...

create or replace procedure addn(a in number,b in number, c 
out number)
 is
 begin
 c:=a+b;
 dbms_output.put_line(c);
 end addn;

Now we can call the in and out parameters as

declare a variable for the out parameter as

var n number;
exec addn(5,10,:n);
print n;

Thanks yaar !!!!!!!!