Java Reference
In-Depth Information
Nested Statements
As you have seen,
if-else
statements and
if
statements contain smaller statements
within them. Thus far, we have used compound statements and simple statements,
such as assignment statements, as these smaller substatements, but there are other pos-
sibilities. In fact, any statement at all can be used as a subpart of an
if-else
statement
or other statement that has one or more statements within it.
When nesting statements, you normally indent each level of nested substatements,
although there are some special situations (such as a multiway
if-else
statement)
where this rule is not followed.
indenting
Self-Test Exercises
1. Write an
if-else
statement that outputs the word
"High"
if the value of the vari-
able
score
is greater than 100 and outputs
"Low"
if the value of
score
is at most
100. The variable
score
is of type
int
.
2. Suppose
savings
and
expenses
are variables of type
double
that have been given
values. Write an
if-else
statement that outputs the word
"Solvent"
, decreases
the value of
savings
by the value of
expenses
, and sets the value of
expenses
to
zero, provided that
savings
is larger than
expenses
. If, however,
savings
is less
than or equal to
expenses
, the
if-else
statement should simply output the word
"Bankrupt"
without changing the value of any variables.
3. Suppose
number
is a variable of type
int
. Write an
if-else
statement that outputs
the word
"Positive"
if the value of the variable
number
is greater than 0 and out-
puts the words
"Not positive"
if the value of
number
is less than or equal to 0.
4. Suppose
salary
and
deductions
are variables of type
double
that have been given
values. Write an
if-else
statement that outputs the word
"Crazy"
if
salary
is
less than
deductions
; otherwise, it should output
"OK"
and set the variable
net
equal to
salary
minus
deductions
.
Multiway
if-else
Statement
The
multiway
if-else
statement
is not really a different kind of Java statement. It is
simply ordinary
if-else
statements nested inside of
if-else
statements, but it is
thought of as a different kind of statement and is indented differently from other
nested statements so as to reflect this thinking.
The syntax for a multiway
if-else
statement and a simple example are given in the
box entitled “Multiway
if-else
Statement.” Note that the Boolean expressions are
aligned with one another, and their corresponding actions are also aligned with one
another. This makes it easy to see the correspondence between Boolean expressions
and actions. The Boolean expressions are evaluated in order until a
true
Boolean
expression is found. At that point, the evaluation of Boolean expressions stops, and the
multiway
if-else
statement
