Java Reference
In-Depth Information
• Integer division (p. 51) yields an integer quotient.
• The remainder operator,
%
(p. 51), yields the remainder after division.
• Arithmetic expressions must be written in straight-line form (p. 51).
• If an expression contains nested parentheses (p. 52), the innermost set is evaluated first.
• Java applies the operators in arithmetic expressions in a precise sequence determined by the rules
of operator precedence (p. 52).
• When we say that operators are applied from left to right, we're referring to their associativity
(p. 52). Some operators associate from right to left.
• Redundant parentheses (p. 53) can make an expression clearer.
Section 2.8 Decision Making: Equality and Relational Operators
•The
if
statement (p. 54) makes a decision based on a condition's value (true or false).
•Conditions in
if
statements can be formed by using the equality (
==
and
!=
) and relational (
>
,
<
,
>=
and
<=
) operators (p. 54).
•An
if
statement begins with keyword
if
followed by a condition in parentheses and expects one
statement in its body.
• The empty statement (p. 57) is a statement that does not perform a task.
Self-Review Exercises
2.1
Fill in the blanks in each of the following statements:
a)
A(n)
begins the body of every method, and a(n)
ends the body of
every method.
b)
You can use the
statement to make decisions.
c)
begins an end-of-line comment.
d)
,
and
are called white space.
e)
are reserved for use by Java.
f)
Java applications begin execution at method
.
g)
Methods
,
and
display information in a command win-
dow.
2.2
State whether each of the following is
true
or
false
. If
false
, explain why.
a)
Comments cause the computer to print the text after the
//
on the screen when the pro-
gram executes.
b)
All variables must be given a type when they're declared.
c)
Java considers the variables
number
and
NuMbEr
to be identical.
d)
The remainder operator (
%
) can be used only with integer operands.
e)
The arithmetic operators
*
,
/
,
%
,
+
and
-
all have the same level of precedence.
2.3
Write statements to accomplish each of the following tasks:
a)
Declare variables
c
,
thisIsAVariable
,
q76354
and
number
to be of type
int
.
b)
Prompt the user to enter an integer.
c)
Input an integer and assign the result to
int
variable
value
. Assume
Scanner
variable
input
can be used to read a value from the keyboard.
d)
Print
"This is a Java program"
on one line in the command window. Use method
System.out.println
.
e)
Print
"This
is
a
Java
program"
on two lines in the command window. The first line
should end with
Java
. Use method
System.out.printf
and two
%s
format specifiers.
f)
If the variable
number
is not equal to
7
, display
"The
variable
number
is
not
equal
to
7"
.
