Chapter 4 (Decision-Making)

Question 1

The ________ structure starts with the evaluation of a ________ expression, and takes one of two paths, based on the outcome of that evaluation.

Answer 1

selection; Boolean

Question 2

selection statements that execute when condition is true begin with __ ___

Answer 2

if then

Question 3

Else statements begin a path execution for when a _______ is false.

Answer 3

condition

Question 4

The if keyword is also called an if-then _____.

Answer 4

clause

Question 5

Are else clauses required to be consequent after an if-then clause?

Answer 5

No, they are not required.

Question 6

These are binary operators (like arithmetic operators). They require 2 operands. They apply arithmetic symbols, but are used in selection structures rather than a literal mathematical formula.

Answer 6

Relational comparison operators

Question 7

This evaluates as true when its operands are equivalent.

Answer 7

Equivalency operator ( = )

Question 8

What is this <> called?

Answer 8

Not-equal-to operator.

Question 9

Both operands in a comparison expression must be the same…

Answer 9

data type.

Question 10

In any comparison, the two values can be either ______ or _______.

Answer 10

variables or constants

Question 11

This describes an expression that always evaluates to the same value. Because it will always return true, or always return false, it is a waste of processing power and logically redundant.

Answer 11

Trivial expressions.

Question 12

Are trivial expressions legal?

Answer 12

Yes. They are legal, but redundant.

Question 13

Assigning an unnamed literal constant to another unnamed literal constant, or comparing the two for a Boolean output, is an example of a _______ _________.
(i.e. 30 = 40)

Answer 13

trivial expression.

Question 14

What are the two reasons why would the comparison “black” < “blue” return as true?

Answer 14

1. They are the same data type (string), so comparing them is legal.
2. “black” precedes “blue” alphabetically.

Question 15

String variables can only be considered equal if they are _______, including the spacing and case-sensitivity attributes (uppercase vs. lowercase)

Answer 15

identical

Question 16

!= is another way of displaying which operator?

Answer 16

The not-equal-to operator ( <> )

Question 17

What is it called when you make multiple evaluations before an outcome is determined?

Answer 17

“Compound condition”

Question 18

A decision that uses an AND expression can be constructed using a…..

Answer 18

nested decision.

Question 19

What is another phrase for a series of nested if statements?

Answer 19

a “Cascading If statement”

Question 20

In an AND decision, it is best to first evaluation the condition that is less likely to be ____

Answer 20

true.

Question 21

Why is it better to evaluate the condition that is less likely to be true first in an AND decision?

Answer 21

Because it eliminates as many instances of the second decision as possible, thus speeding up processing time.

Question 22

A conditional AND operator is the same as a….

Answer 22

AND operator

Question 23

an AND operator allows you to ask how many questions in a single comparison/expression?

Answer 23

two or more

Question 24

When you use one or more AND operators to combine two or more Boolean expressions, each Boolean expression must be true for…

Answer 24

the entire expression to be evaluated as true. Both conditions must return as TRUE or YES.

Question 25

The Boolean expression placed first (to the left of the AND operator) is the one that will be evaluated first. That means that cases that are eliminated based on the first evaluation will NOT proceed to the second one. This built-in feature of many programming languages is called....

Answer 25

short-circuit evaluation.

Question 26

These are diagrams used in mathematics and logic to help describe the truth of an entire expression based on the truth of its parts.

Answer 26

Truth tables

Question 27

Computers make decisions one at a time, from _____ to ______.

Answer 27

left to right

Question 28

What are the 3 benefits to using AND operators instead of nested/cascading if statements?

Answer 28

1. more concise. 2. less error-prone 3. easier to understand

Question 29

in an OR decision, either one condition or some other condition must be met in order for....

Answer 29

the evaluation to return as True and some action begins to take place.

Question 30

It is better to evaluate the condition that is more likely to be true first in an ___ _______.

Answer 30

OR decision

Question 31

the OR operator is also called the ______ OR operator.

Answer 31

Conditional

Question 32

When x OR y are each false individually, the entire expression is read as....

Answer 32

False.

Question 33

The NOT operator ______ the meaning of a Boolean expression.

Answer 33

reverses

Question 34

the NOT operator is a ______ operator.

Answer 34

unary

Question 35

You do not use these in between two expressions; rather, you use it in front of a single expression.

Answer 35

unary operators

Question 36

This compares a variable to a series of values that mark the limiting ends of _____.

Answer 36

range check; ranges.

Question 37

another phrase for a path that is "dead"

Answer 37

unreachable path

Question 38

When you combine AND and OR operators within the same statement, the AND operators take ________.

Answer 38

precedence; their Boolean values are evaluated first.

Question 39

You can alter the computer's intuitive logic of giving an AND operator's value precedence by using _______ around the OR expression.

Answer 39

parentheses

Question 40

A _____ Boolean expression is one that always has the same value.

Answer 40

trivial

Question 41

If x <= y is True, then x __ y is False.

Answer 41

>

Question 42

``` What does the following mean? if x > 10 then if y > 10 then output "X" endif endif ```

Answer 42

if x > 10 AND y > 10 then output "X"