Java Reference
In-Depth Information
Theconditionaloperatorisusefulformakingadecisionbyevaluatingandreturning
one of two operands based upon the value of a third operand. The following example
converts a Boolean value to its integer equivalent (1 for true and 0 for false):
boolean b = true;
int i = b ? 1 : 0; // 1 assigns to i
Equality Operators
The equality operators consist of equality (
==
) and inequality (
!=
). These operators
comparetheiroperandstodeterminewhethertheyareequalorunequal.Theformerop-
erator returns true when equal; the latter operator returns true when unequal. For ex-
ample,eachof
2 == 2
and
2 != 3
evaluatestotrue,whereaseachof
2 == 4
and
4 != 4
evaluates to false.
When it comes to object operands (discussed in
Chapter 2
), these operators do not
comparetheircontents.Forexample,
"abc" == "xyz"
doesnotcompare
a
with
x
.
discusses this concept further),
==
compares the references to these objects.
Logical Operators
The logical operators consist of logical AND (
&
), logical complement (
!
), logical ex-
clusive OR (
^
), and logical inclusive OR (
|
). Although these operators are similar
to their bitwise counterparts, whose operands must be integer/character, the operands
passed to the logical operators must be Boolean. For example,
!false
returns true.
Also,whenconfrontedwith
age > 64 & stillWorking
,logicalANDevaluates
both subexpressions. This same pattern holds for logical exclusive OR and logical in-
clusive OR.
Member Access Operator
Thememberaccessoperator(
.
)isusedtoaccessaclass'smembersoranobject'smem-
bers. For example,
String s = "Hello"; int len = s.length();
re-
turnsthelengthofthestringassignedtovariable
s
.Itdoessobycallingthe
length()
Arraysarespecialobjectsthathaveasingle
length
member.Whenyouspecifyan
arrayvariablefollowedbythememberaccessoperator,followedby
length
,theres-
ultingexpressionreturnsthenumberofelementsinthearrayasa32-bitinteger.Forex-
ample,
ages.length
returnsthelengthof(thenumberofelementsin)thearraythat
ages
references.
