Answers to Self-Review Questions - Java Software Solutions: Foundations of Program Design - page 742

SR 2.23 After executing the statement, diameter holds the value 20. First, the

current value of diameter (5) is multiplied by 4, and then the result is
stored back in diameter .

SR 2.24 Operator precedence is the set of rules that dictates the order in which

operators are evaluated in an expression.

SR 2.25 The evaluations of the expressions are

a. 15 + 7 * 3

15 + 21 36

b. (15 + 7) * 3

22 * 3 66

c. 3 * 6 + 10 / 5 + 5 18 + 2 + 5

25

d. 27 % 5 + 7 % 3

2 + 1 3

e. 100 / 2 / 2 / 2

50 / 2 / 2 25 / 2 = 12

f. 100 / ( 2 / 2) / 2

100 / 1 / 2 100 / 2 = 50

SR 2.26 Expression a is valid. Expression b is invalid because there are two

open parentheses but only one close parenthesis. Similarly with expres-
sion c, where there are two open parentheses but no close parenthesis.
Expression d might be a valid algebraic expression in an algebra book,
but it is not a valid expression in Java. There is no operator between the
operands 2 and ( 4 ).

SR 2.27 After the sequence of statements, the value in result is 8.

SR 2.28 After the sequence of statements, the value in result is 8. Note that

even though result was set to base + 3 , changing the value of base to
7 does not retroactively change the value of result .

SR 2.29 An assignment operator combines an operation with assignment. For

example, the += operator performs an addition, then stores the value
back into the variable on the left-hand side.

SR 2.30 After executing the statement, weight holds the value 83. The assign-

ment operator −= modifies weight by first subtracting 17 from the cur-
rent value (100), then storing the result back into weight .

2.5 Data Conversion
SR 2.31 A widening conversion tends to go from a small data value, in terms

of the amount of space used to store it, to a larger one. A narrowing
conversion does the opposite. Information is more likely to be lost in a
narrowing conversion, which is why narrowing conversions are consid-
ered to be less safe than widening ones.

SR 2.32 The conversions are: a. widening, b. narrowing, c. widening, d. widening,

e. widening.