Section 4 Lesson 4: Iterative Control: While and For Loops

Iterative Control: While and For Loops
     
  1.  Look at the following code fragment:
i := 2;
WHILE i < 3 LOOP
   i := 4;
   DBMS_OUTPUT.PUT_LINE('The counter is: ' || i);
END LOOP;

How many lines of output will be displayed?
(1) Points
     
    No lines
    One line (*)
    Two lines
    The block will fail because you cannot use DBMS_OUTPUT.PUT_LINE inside a loop.
     
  2.  Look at the following block:
DECLARE
   v_date DATE := SYSDATE;
BEGIN
   WHILE v_date < LAST_DAY(v_date) LOOP
     v_date := v_date + 1;
   END LOOP;
   DBMS_OUTPUT.PUT_LINE(v_date);
END;

If today's date is 17th April 2007, what will be displayed when this block executes?
(1) Points
     
    01-MAY-07
    31-DEC-07
    4/30/2007 (*)
    4/17/2007
     
  3.  Which statement best describes when a FOR loop should be used? (1) Points
     
    When an EXIT WHEN statement must be coded.
    When an implicitly declared counter must increase by 1 in each iteration of the loop. (*)
    When we want to exit from the loop when a Boolean variable becomes FALSE.
    When the statements inside the loop must execute at least once.
     
  4.  You should use a WHILE loop when the number of iterations of the loop is known in advance. True or False? (1) Points
     
    True
    False (*)
     
  5.  Look at this code fragment: FOR i IN 1 .. 3 LOOP i := 4; DBMS_OUTPUT.PUT_LINE('The counter is: ' || i); END LOOP; How many lines of output will be displayed? (1) Points
     
    One
    Three
     Four
     The block will fail because you cannot change the value of i inside the loop. (*)
     
  6.  In a FOR loop, an explicitly declared counter is automatically incremented by 1 for each iteration of the loop. True or False? (1) Points
     
    True
     False (*)
     
 7.  In a WHILE loop, the controlling condition is checked at the start of each iteration. True or False?  (1) Points
     
    True (*)
     False
     
  8.  You want a loop that counts backwards from 10 through 1. How do you code that? (1) Points
     
    FOR i IN 10 .. 1 LOOP
    FOR i IN 1 .. 10 BY -1 LOOP
    FOR i IN REVERSE 1 .. 10 LOOP (*)
    FOR i IN REVERSE 10 .. 1 LOOP