Chapter 5: Decisions

Question 1

relational operator

Answer 1

An operator that compares two values, yielding a Boolean result.

Question 2

lexicographic order

Answer 2

Ordering strings in the same order as in a dictionary, by skipping all matching characters and comparing the first non-matching characters of both strings. For example, “orbit” comes before “orchid” in lexicographic ordering. Note that in Java, unlike a dictionary, the ordering is case sensitive: Z comes before a.

Question 3

null reference

Answer 3

A reference that does not refer to any object.

Question 4

black-box testing

Answer 4

Testing a method without knowing its implementation.

Question 5

white-box testing

Answer 5

Testing methods by taking their implementations into account, in contrast to black-box test ing; for example, by selecting boundary test cases and ensuring that all branches of the code are covered by some test case.

Question 6

code coverage

Answer 6

A measure of the amount of source code that has been executed during testing.

Question 7

boundary test cases

Answer 7

A test case involving values that are at the outer boundary of the set of legal values. For example, if a method is expected to work for all nonnegative integers, then 0 is a boundary test case.

Question 8

trace messages

Answer 8

A message that is printed during a program run for debugging purposes.

Question 9

Boolean operator

Answer 9

An operator that can be applied to Boolean values. Java has three Boolean operators: &&, ||, and !.

Question 10

De Morgan’s Law

Answer 10

A law about logical operations that describes how to negate expressions
formed with and and or operations.