ERROR at line 8: PL/SQL: Statement ignored - oracle10g

Question

ERROR at line 8: PL/SQL: Statement ignored
CREATE OR REPLACE PROCEDURE POS(A IN NUMBER,M IN NUMBER,TOTAL OUT NUMBER)
AS
BEGIN
TOTAL:=0;
WHILE A>0 LOOP
M:=MOD(A,10);
TOTAL:=TOTAL+M;
A:=(A/10);//statement ignored error
END LOOP;
DBMS_OUTPUT.PUT_LINE(TOTAL);
END;
DECLARE
X NUMBER;
Y NUMBER:=5;
Z NUMBER;
BEGIN
POA(X,Y,Z);
END;

Answer 1

OK, I've had a look at your procedure and tried to resolve the issues you are having with it.
You haven't explained much (or indeed anything) about what you are trying to achieve which makes it really difficult to get you an answer.
People on here really want to help but you have to at least give us the tools with witch to provide that help.
Anyhow, with a host of assumptions, here is my version of your procedure with the following assumptions:
Your procedure is names POS (you name it POS in the procedure definition but then try to execute it as POA).
Your main issue was trying to assign a new value to input parameter "a" within the loop. As it is an input parameter it is immutable and you cannot assign new values to it. I have got round this by declaring a local variable "v_iter" and assigning that the value of "a" and then using it to control the loop.
I have added an "exception" section to handle any unexpected errors and output that error via DBMS_OUTPUT. You might want to make this more robust.
You do not test to check if the input parameter "a" is null or a valid number (i.e. not negative), you might want to do this to make your procedure more robust.
Here is the changed code:
CREATE OR REPLACE
PROCEDURE POS (
a IN NUMBER,
m IN NUMBER,
total OUT NUMBER
)
AS
— Declare variables
v_iter NUMBER := a;
BEGIN
— Initialise total
total := 0;
— Loop through “v_iter”
WHILE v_iter > 0
LOOP
m := MOD(v_iter,10);
total := total + m;
v_iter := (v_iter/10);
END LOOP;
DBMS_OUTPUT.put_line(total);
EXCEPTION
WHEN others
THEN
— Output and raise an error;
DBMS_OUTPUT.put_line(sqlerrm);
RAISE;
END POS;
/
To call it:
DECLARE
X NUMBER;
Y NUMBER:=5;
Z NUMBER;
BEGIN
POS(X,Y,Z);
END;
/
Hope it helps.