java第三章 _原创精品文档.pdfVIP

java第三章

1.Whichofthefollowingcodedisplaystheareaofacircleif

theradiusispositive.

a.if(radius!=0)System.out.println(radius*radius*3.14159);

b.if(radius=0)System.out.println(radius*radius*

3.14159);

c.if(radius0)System.out.println(radius*radius*3.14159);

d.if(radius=0)System.out.println(radius*radius*

3.14159);

#

2.Supposex=0andy=0whatisxafterevaluatingthe

expression(y0)(1x++).

a.1

b.0

c.-1

#

3.Thefollowingcodedisplays___________.

doubletemperature=50;

if(temperature=100)

System.out.println(toohot);

elseif(temperature=40)

System.out.println(toocold);

else

System.out.println(justright);

a.toohot

b.justright

c.toocold

d.toohottoocoldjustright

#

4.Whatistheprintoutofthefollowingswitchstatement?

charch=a;

switch(ch){

casea:

caseA:

System.out.print(ch);break;

caseb:

caseB:

System.out.print(ch);break;

casec:

caseC:

System.out.print(ch);break;

cased:

caseD:

System.out.print(ch);

}

a.a

b.aa

c.abcd

d.ab

e.abc

#

5.Theorderoftheprecedence(fromhightolow)ofthe

operatorsbinary+,*,,||is:

a.,||,*,+

b.*,+,,||

c.*,+,||,

d.||,,*,+

#

6.Analyzethefollowingcodefragmentsthatassigna

booleanvaluetothevariableeven.

Code1:

if(number%2==0)

even=true;

else

even=false;

Code2:

even=(number%2==0)?true:false;

Code3:

even=number%2==0;

a.Allthreearecorrect,butCode1ispreferred.

b.Code2hasacompileerror,becauseyoucannothavetrue

andfalseliteralsintheconditionalexpression.

c.Allthreearecorrect,butCode3ispreferred.

d.Allthre