Chapter 5: Decisions

Question 1

What does the if statement allow a program to do?

Answer 1

carry out different actions depending on the nature of the data to be processed

Question 2

What does a relational operator test?

Answer 2

the relationship between two values

Question 3

What relationship operators do programmers use to compare numbers?

Answer 3

<, <=, >, >=, ==, !=

Question 4

Why don’t you check for equality when comparing floating-point numbers?

Answer 4

because they’re could be a rounding error. Instead, test whether they are close enough

Question 5

What threshhold value do we say is “close enough”

Answer 5

10^(-14) OR 1e-14

Question 6

T/F: use the == operator to compare strings

Answer 6

Fuck NO!

Question 7

What method do you use to compare strings?

Answer 7

the equal method

Question 8

What does the compareTo method do?

Answer 8

compares strings in lexographic order

Question 9

What is ‘A’ in lexographic order?

Answer 9

65

Question 10

What is ‘a’ in lexographic order

Answer 10

97

Question 11

string1.compareTo(string2) == 0 returns true. What is true about the two strings?

Answer 11

they are identical

Question 12

What would happen if you use the == method on objects?

Answer 12

it would test whether two object references are identical

Question 13

What method should you use to compare the values of an object?

Answer 13

equals

Question 14

What does the null reference refer to?

Answer 14

no object

Question 15

What operator do you use to test whether an object is a null reference?

Answer 15

==

Question 16

How can you evaluate complex decisions?

Answer 16

use multiple if statements

Question 17

What order should you test conditions when using multiple if statements?

Answer 17

test general conditions after more specific conditions

Question 18

When are statements nested?

Answer 18

when a descision statement is contained inside the branch of another descision statement

Question 19

When are nested descisions required?

Answer 19

for problems that have two levels of descision making

Question 20

What is black-box testing?

Answer 20

a testing method that does not take the structure of the implementation into account

Question 21

What is white-box testing?

Answer 21

testing that uses information about the structure of a program

Question 22

What is code coverage?

Answer 22

a measure of how many parts of a program have been tested

Question 23

What are boundary test cases?

Answer 23

legal values that lie at the boundary of the set of acceptable inpits

Question 24

What values does boolean have?

Answer 24

true and false

Question 25

What is a boolean operator?

Answer 25

an operator that combines boolean conditions

Question 26

What are the two boolean operators?

Answer 26

&& (and) and || (or)

Question 27

What operator is used to invert a condition?

Answer 27

! (not)

Question 28

What does the hasNextInt ensure?

Answer 28

that the next input is a number