Starting Out with Python 4e (Gaddis)
Chapter 3 Decision Structures and Boolean Logic
TRUE/FALSE
1. The Python language is not sensitive to block structuring of code.
ANS: F
2. The if statement causes one or more statements to execute only when a Boolean expression is true.
ANS: T
3. Python allows you to compare strings, but it is not case sensitive.
ANS: F
4. Nested decision statements are one way to test more than one condition.
ANS: T
5. Python uses the same symbols for the assignment operator as for the equality operator.
ANS: F
6. The not operator is a unary operator which must be used in a compound expression.
ANS: F
7. Short -circuit evaluation is only performed with the not operator.
ANS: F
8. Expressions that are tested by the if statement are called Boolean expressions.
ANS: T
9. Decision structures are also known as selection structures.
ANS: T
10. An action in a single alternative decision structure is performed only when the condition is true.
ANS: T
11. The following statement will check to see if the turtle’s pen color is ‘green’:
if turtle.pencolor() = ‘green’
ANS: F
12. The following code snippet will change the turtle’s pen size to 4 if it is presently less than 4:
if turtle.pensize() < 4:
turtle.pensize(4)
ANS: T
MULTIPLE CHOICE
1. A(n) __________ structure is a logical design that controls the order in which a set of statements execute.
a.
function
b.
control
c.
sequence
d.
iteration
ANS: B
2. The decision structure that has two possible paths of execution is known as
a.
single alternative
b.
double alternative
c.
dual alternative
d.
two alternative
ANS: C
3. Multiple Boolean expressions can be combined by using a logical operator to create __________ expressions.
a.
sequential
b.
logical
c.
compound
d.
mathematical
ANS: C
4. When using the __________ logical operator, one or both of the subexpressions must be true for the compound expression to be true.
a.
or
b.
and
c.
not
d.
maybe
ANS: A
5. Which logical operators perform short-circuit evaluation?
a.
or, not
b.
not, and
c.
or, and
d.
and, or, not
ANS: C
6. Which of the following is the correct if clause to determine whether y is in the range 10 through 50, inclusive?
a.
if 10 < y or y > 50:
b.
if 10 > y and y < 50:
c.
if y >= 10 and y <= 50:
d.
if y >= 10 or y <= 50:
ANS: C
7. A Boolean variable can reference one of two values which are
a.
yes or no
b.
True or False
c.
T or F
d.
Y or N
ANS: B
8. What is the result of the following Boolean expression, given that x = 5, y = 3, and z = 8?
x < y or z > x
a.
True
b.
False
c.
8
d.
5
ANS: A
9. What is the result of the following Boolean expression, given that x = 5, y = 3, and z = 8?
x < y and z > x
a.
True
b.
False
c.
8
d.
5
ANS: B
10. What is the result of the following Boolean expression, given that x = 5, y = 3, and z= 8?
not (x < y or z > x) and y < z
a.
True
b.
False
c.
8
d.
5
ANS: B
11. What does the following expression mean?
x <= y
a.
x is less than y
b.
x is less than or equal to y
c.
x is greater than y
d.
x is greater than or equal to y
ANS: B
12. Which of the following is the correct if clause to determine whether choice is anything other than 10?
a.
if choice != 10:
b.
if choice != 10
c.
if choice <> 10:
d.
if not(choice < 10 and choice > 10):
ANS: A
13. When using the __________ logical operator, both subexpressions must be true for the compound expression to be true.
a.
or
b.
and
c.
not
d.
either or or and
ANS: B
14. In Python the __________ symbol is used as the not-equal-to operator.
a.
==
b.
<>
c.
<=
d.
!=
ANS: D
15. In Python the __________ symbol is used as the equality operator.
a.
==
b.
<>
c.
<=
d.
!=
ANS: A
16. Which of the following will hide the turtle if it is visible?
a.
if turtle.isvisible():
turtle.invisible()
b.
if turtle.isvisible
turtle.hideturtle()
c.
turtle.isvisible():
turtle.hide()
d.
if turtle.isvisible():
turtle.hideturtle()
ANS: D
17. Which of the following will determine if the turtle's pen is up and will change it to down if that is the case?
a.
if turtle.isup():
turtle.isdown()
b.
if turtle.isdown
turtle.penup()
c.
if not(turtle.isdown()):
turtle.pendown()
d.
if not(turtle.penup())
turtle.penup()
ANS: C
COMPLETION
1. The ___________ statement is used to create a decision structure.
ANS: if
2. In flowcharting, the __________ symbol is used to represent a Boolean expression.
ANS: diamond
3. A(n) __________ decision structure provides only one alternative path of execution.
ANS: single alternative
4. In a decision structure, the action is ___________ executed because it is performed only when a specific condition is true.
ANS: conditionally
5. A(n) __________ operator determines whether a specific relationship exists between two values.
ANS: relational
6. A(n) __________ statement will execute one block of statements if its condition is true or another block if its condition is false.
ANS: if-else
7. Python provides a special version of a decision structure known as the __________ statement, which makes the logic of the nested decision structure simpler to write.
ANS: if-elif-else
8. The logical __________ operator reverses the truth of a Boolean expression.
ANS: not
9. Boolean variables are commonly used as __________ to indicate whether a specific condition exists.
ANS: flags
10. A(n) ___________ expression is made up of two or more Boolean expressions.
ANS: compound
11. The turtle.isdown() function returns ___________ if the turtle's pen is down.
ANS: True