M3 CH5

Question 1

A ____________________________ - controlled loop uses a true/false condition to control the number of times that it repeats.
Boolean
condition
decision
count

Answer 1

condition

Question 2

A __________________________- controlled loop repeats a specific number of times.
Boolean
condition
decision
count

Answer 2

count

Question 3

Each repetition of a loop is known as a(n) ______________________________.
cycle
revolution
orbit
iteration

Answer 3

iteration

Question 4

The While loop is a _______________________ type of loop.
pretest
postest
prequalified
post iterative

Answer 4

pretest

Question 5

The Do-While loop is a ______________________type of loop.
pretest
posttest
prequalified
post iterative

Answer 5

posttest

Question 6

The For loop is a ______________________________________ type of loop.
pretest
posttest
prequalified
post iterative

Answer 6

pretest

Question 7

A(n) _______________________________ loop has no way of ending and repeats until the program is interrupted.
indeterminate
interminable
infinite
timeless

Answer 7

infinite

Question 8

A __________________________ loop always executes at least once.
pretest
postest
condition-controlled
count-controlled

Answer 8

postest

Question 9

A(n) ________________________________ is a special value that signals when there are no more items from a list of items to be processed. This value cannot be mistaken as an item from the list.
sentinel
flag
signal
accumulator

Answer 9

sentinel

Question 10

A condition-controlled loop always repeats a specific number of times.
True or False

Answer 10

False

Question 11

The While loop is a pretest loop
True or False

Answer 11

True

Question 12

The Do-While loop is a pretest loop.
True or False

Answer 12

False

Question 13

You should not write code that modifies the contents of the counter variable in the body of a For loop.

Answer 13

True

Question 14

You cannot display the contents of the counter variable in the body of a loop.
True or False

Answer 14

False

Question 15

It is not possible to increment a counter variable by any value other than 1.
True or False

Answer 15

False

Question 16

The following statement decrements the variable x: Set x = x - 1.
True or False

Answer 16

True

Question 17

It is not necessary to initialize accumulator variables.
True or False.

Answer 17

False

Question 18

In a nested loop, the inner loop goes through all of its iterations for every single iteration of the outer loops.
True or False

Answer 18

True

Question 19

To calculate the total number of iterations of a nested loop, add the number of iterations of all the loops.
True or False

Answer 19

False

Question 20

Why should you indent the statements in the body of a loop?

Answer 20

By indenting the that statements in the body of the loop you visually set them apart from the surrounding code. This makes your program easier to read and debug. Also, this is similar to the style that most programmers follow when writing loops in actual code.

Question 21

Describe the difference between pretest loops and posttest loops.

Answer 21

Pretest loops tests its condition before performing an iteration. Because the test is done at the beginning of the loop, you usually have to perform some steps prior to the loop to make sure that the loop executes at least once.
Posttest loops performs an iteration before testing its condition. The posttest loop always perform at least once iteration even if its condition is false to begin with.

Question 22

What is a condition-controlled loop?

Answer 22

A condition-contrlled loop uses a true/false condition to control the number of times that it repeats.

Question 23

What is a count-controlled loop?

Answer 23

A count-controlled loop iterates a specific number of times.

Question 24

What is an infinite loop? Write the code for an infinite loop.

Answer 24

An infinite loop continues to repeat until the program is interrupted. Infinite loops usually occur when the programmer forgets to write code inside the loop that makes the test condition false.

Declare Integer awesome = 5

While awesome > 0
set awesome = awesome + 1
display awesome
End While

Question 25

A For loop looks like what other loop in a flowchart?

Answer 25

While loop

Question 26

Why is it critical that accumulator variables are properly initialized?

Answer 26

When the loop finishes, the accumulator will contain the total of the numbers that were read by the loop. This is a critical step. Each time the loop reads a number, it adds it to the accumulator. If the accumulator starts with any value other than 0, it will not contain the correct total when the loop finishes.

Question 27

What is the advantage of using a sentinel?

Answer 27

When processing a long list of values with a loop, perhaps a better technique is to use a sentinel. A sentinel is a special value that marks the end of a list of items. When a program reads the sentinel value it knows it has reached the end of the list, so the loop terminates.

Question 28

Why must the value chosen for use as a sentinel be carefully selected?

Answer 28

A sentinel value must be unique enough that it will not be mistaken as a regular value in the list.