what is program in plsql to check whether it is prime using function and procedure - plsql

Question

declare
K number;
Lnumber;
f number;
function prime(n in number, I in number) return is flag
begin
i:=2;
flag:=1;
n:=&n;
for i in 2..n/2
loop
if mod(n,i)=0
then
flag:=0;
exit;
end if;
end loop;
if flag=1
then
dbms_output.put_line('prime');
else
dbms_output.put_line('not prime');
end if;
return flag;
end;
begin
k:=4;
L:=1;
f:= prime(n,i);
dbms_output.put_line(given number is ||flag);
end;
/
I am getting output as this I wonder what is wrong with my code:
Enter value for n: 4
old 9: n:=&n;
new 9: n:=4;
declare
*
ERROR at line 1:
ORA-06540: PL/SQL: compilation error
ORA-06553: PLS-906: Compilation is not possible
q2
SQL> DECLARE
num NUMBER;
3 c NUMBER;
4
5 PROCEDURE fact (x IN NUMBER, f OUT NUMBER)
6 IS
7 l_var NUMBER := 1;
8 BEGIN
9 FOR i IN 1 .. x
10 LOOP
11 l_var := l_var * i;
12 END LOOP;
13
14 f := l_var;
15 END;
16 BEGIN
17 num := 6;
18 fact (num, c);
19 DBMS_OUTPUT.put_line (' Factorial of ' || num || ' is ' || c);
20 END;
.
in this 2nd code the result is not getting displayed , not only for this even for other codes it is showing the line PL/SQL procedure successfully completed. but the results are not displaying what is wrong with it

Answer 1

A fixed version of q1 might be something like this (comments inline):
declare
-- k number; -- not used
-- l number; -- previously "lnumber;" not used anyway
f number;
function prime
( n in number ) -- "i" parameter never used
return number -- added return type
is
flag number := 1; -- added datatype, initial value and semicolon
begin
-- i := 2; -- Can't modify an IN parameter
-- flag := 1; -- not needed, can assign a value when declaring
-- n := &n; -- Can't modify an IN parameter
for i in 2 .. n / 2 loop
if mod(n, i) = 0 then
flag := 0;
exit;
end if;
end loop;
if flag = 1 then
dbms_output.put_line('prime');
else
dbms_output.put_line('not prime');
end if;
return flag;
end prime; -- added closing tag for clarity
begin
-- k := 4; -- not used
-- l := 1; -- not used
-- f := prime(n, i); -- n and i are not declared
f := prime(123);
dbms_output.put_line('prime check returns '|| f); -- added quotes, changed "flag" to "f"
end;
Also I formatted the code to make it more readable. This also helps when writing code, as it keeps the structure clearly visible and makes some errors more obvious.
q2 works for me, so you probably just need to check how whatever tool you are using displays dbms_output. In some tools there is a checkbox, others require a set server output on command.
You can also provide a function implementation of your factorial procedure:
declare
num number;
c number;
procedure fact
( num in number
, f out number )
is
begin
f := 1;
for i in 2 .. num loop
f := f * i;
end loop;
end fact;
function fact
( num number )
return number
is
f number;
begin
fact(num, f);
return f;
end fact;
begin
num := 6;
fact(num, c);
dbms_output.put_line('Factorial of ' || num || ' is ' || c);
dbms_output.put_line('Factorial of ' || num || ' is ' || fact(num));
end;