Java Reference
In-Depth Information
if (numMonthlySales > 100)
wage += bonus;
Ifthenumberofmonthlysalesexceeds100,
numMonthlySales > 100
evaluates
totrueandthe
wage += bonus;
assignmentstatementexecutes.Otherwise,thisas-
signment statement does not execute.
If-Else Statement
Theif-elsestatementevaluatesaBooleanexpressionandexecutesoneoftwostatements
dependingonwhetherthisexpressionevaluatestotrueorfalse.Thisstatementhasthe
following syntax:
if (
Boolean expression
)
statement1
else
statement2
If-else consists of reserved word
if
, followed by a
Boolean expression
in
parentheses,followedbya
statement1
toexecutewhen
Boolean expression
evaluatestotrue,followedbya
statement2
toexecutewhen
Boolean expres-
sion
evaluates to false.
The following example demonstrates this statement:
if ((n&1) == 1)
System.out.println("odd");
else
System.out.println("even");
Thisexampleassumestheexistenceofan
int
variablenamed
n
thathasbeeninitial-
izedtoaninteger.Itthenproceedstodeterminewhethertheintegerisodd(notdivisible
by 2) or even (divisible by 2).
TheBooleanexpressionfirstevaluates
n&1
,whichbitwiseANDs
n
'svaluewith
1
.
Itthencomparestheresultto
1
.Iftheyareequal,amessagestatingthat
n
'svalueisodd
outputs; otherwise, a message stating that
n
's value is even outputs.
Theparenthesesarerequiredbecause
==
hashigherprecedencethan
&
.Withoutthese
parentheses,theexpression'sevaluationorderwouldchangetofirstevaluating
1 == 1
andthentryingtobitwiseANDtheBooleanresultwith
n
'sintegervalue.Thisorderres-
ultsinacompilererrormessagebecauseofatypemismatch:youcannotbitwiseAND
an integer with a Boolean value.
