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1. class Animal { Animal getOne() { return new Animal(); } }  2. class Dog extends Animal {  3. // insert code here   4. }  5.  6. class AnimalTest {  7. public static void main(String [] args) {  8. Animal [] animal = { new Animal(), new Dog() } ;  9. for( Animal a : animal) {  10. Animal x = a.getOne();  11. }  12. }  13. }  和代码:  3a. Dog getOne() {  return new Dog();  }  3b. Animal getOne() {  return new Dog();  }  第 3 行中插入的哪项将编译且运行无异常?() 

  • A、3a行
  • B、3b行
  • C、3a行或3b行
  • D、既非3a,也非3b

参考答案

更多 “ 1. class Animal { Animal getOne() { return new Animal(); } }  2. class Dog extends Animal {  3. // insert code here   4. }  5.  6. class AnimalTest {  7. public static void main(String [] args) {  8. Animal [] animal = { new Animal(), new Dog() } ;  9. for( Animal a : animal) {  10. Animal x = a.getOne();  11. }  12. }  13. }  和代码:  3a. Dog getOne() {  return new Dog();  }  3b. Animal getOne() {  return new Dog();  }  第 3 行中插入的哪项将编译且运行无异常?() A、3a行B、3b行C、3a行或3b行D、既非3a,也非3b” 相关考题
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考题 ( 12 )有如下程序:#include iostreamusing namespace stdclass Animal{public:virtual char* getType () const { return "Animal" ; }virtual char* getVoice () const { return "Voice" ; }};Class Dog : public Animal {public:char* getType ( ) const {return "Dog" ; }char* getVoice ( ) const {return "Woof"}};void type ( Animal a ) {couta.getType ( ) ; }void speak ( Animal a ) {couta.getVoice ( ) ; }int main ( ) {Dog d; type ( d ) ; cout" speak" ; speak ( d ) ; coutendi;return 0;}运行时的输出结果是【 12 】 。

考题 有如下程序:ncludeiostreamusing namespace std;class Animal{public:virtual char*getType()const{return“Animal”;}virtual char*getVoice()const{return“Voice”;}};class Dog:public Animal{public:char*getType()const{rgturn“Dog”;}char*getVoice()const{retum“Woof”;}};void type(AnimalA){couta.getType();}void speak(AnimalA){couta.getVoice();}int main(){Dog d.type(D);tout“speak”;speak(D);coutendl;return 0;}运行时的输出结果是【 】

考题 下列程序片段中,能通过编译的是( )。A.public abstract class Animal{public void speak( );}B.public abstract class Animal{public void speak( ){};}C.public class Animal{pubilc abstract void speak( );}D.public abstract class Animal{pubile abstract void speak( ){};}

考题 下列程序片段中,能通过编译的是( )。 A.public abstract class Animal{ public void speak;}S 下列程序片段中,能通过编译的是( )。A.public abstract class Animal{ public void speak;}B.public abstract class Animal{ public void speak{);}C.public class Animal{ pubilc abstract void speak;}D.public abstract class Animal{ pubile abstract void speak{};}

考题 在Java中,类Animal中的方法printA()定义如下:  public void printA() {    Int a=10;    Int result =10%3;    System.out.println(result); }  在类Dog中方法printA()定义如下:  public void printA() {   Int a=10;    System.out.println(a/3); }  Dog类的定义如下:  Class Dog extends Animal{…}.  Animal animal=new Dog();  animal.printA();  以上语句输出结果为()。 A、 0B、 1C、 2D、3E、3.3333

考题 10. interface Jumper { public void jump(); }  ......  20. class Animal {}  ......  30. class Dog extends Animal { 31. Tail tail; 32. }  ......  40. class Beagle extends Dog implements Jumper {  41. public void jump() { }  42. }  .......  50. class Cat implements Jumper {  51. public void jump() { }  52. }  Which three are true?()A、 Cat is-a AnimalB、 Cat is-a JumperC、 Dog is-a AnimalD、 Dog is-a JumperE、 Cat has-a AnimalF、 Beagle has-a TailG、 Beagle has-a Jumper

考题 1. public class A {  2. void A() {  3. System.out.println(“Class A”);  4. }  5. public static void main(String[] args) {  6. new A();  7. }  8. }  What is the result?()  A、 Class AB、 Compilation fails.C、 An exception is thrown at line 2.D、 An exception is thrown at line 6.E、 The code executes with no output.

考题 现有:   1.  class HorseRadish {   2.    // insert code here   3.    protected HorseRadish(int x) {    4.      System.out.println("bok choy");  5.    }  6.  }   7.  class Wasabi extends HorseRadish {   8.    public static void main(String [] args) {   9.      Wasabi w = new Wasabi();  10.   }    11. }   分别插入到第 2 行,哪两项允许代码编译并产生"bok choy" 输出结果?() A、 // just a commentB、 protected HorseRadish() { }C、 protected HorseRadish() { this(42);}D、 protected  HorseRadish() { new HorseRadish (42);}

考题 class Animal{ Animal getOne(){return new Animal();}}   class Dog extends Animal{   //insert code here   }   class AnimalTest{   public static void main(String[] args){   Animal[] animal={ new Animal(), new Dog()};   for(Animal a:animal){   Animal x= a.getOne();   }   }   }   和代码:   3a.Dog getOne() { return new Dog();}   3b.Animal getOne() { return new Dog();}   第3行中插入的哪项编译且运行无异常?  A、3a行或3b行B、既非3a,也非3bC、3a行D、3b行

考题 interface Animal {  void soundOff();  }  class Elephant implements Animal {  public void soundOff() {  System.out.println(“Trumpet”);  }  }  class Lion implements Animal {  public void soundOff() { System.out.println(“Roar”);  }  }  class Alpha1 {  static Animal get( String choice ) {  if ( choice.equalsIgnoreCase( “meat eater” )) {  return new Lion();  } else {  return new Elephant();  }  }  }  Which compiles?()  A、 new Animal().soundOff();B、 Elephant e = new Alpha1();C、 Lion 1 = Alpha.get(“meat eater”);D、 new Alpha1().get(“veggie”).soundOff();

考题 11. class Animal { public String noise() { return “peep”; } }  12. class Dog extends Animal {  13. public String noise() { return “bark”; }  14. }  15. class Cat extends Animal {  16. public String noise() { return “meow”; }  17. }  .....  30. Animal animal = new Dog();  31. Cat cat = (Cat)animal;  32. System.out.printIn(cat.noise());  What is the result?() A、 peepB、 barkC、 meowD、 Compilation fails.E、 An exception is thrown at runtime.

考题 现有:  interface Animal {       void eat () ;       }       //insert code here       public class HouseCat extends Feline {       public void eat() { }       }  和五个申明  abstract class Feline implements Animal { }  abstract  class  Feline  implements  Animal  {  void eat () ;  }  abstract class Feline implements Animal { public void eat();}  abstract class Feline implements Animal { public void eat() {}  }  abstract class Feline implements Animal { abstract public void eat();} 结果为:()      A、1B、2C、3D、4

考题 1. import java.util.*;  2. public class Example {  3. public static void main(String[] args) {  4. // insert code here  5. set.add(new integer(2));  6. set.add(new integer(l));  7. System.out.println(set);  8. }  9. }  Which code, inserted at line 4, guarantees that this program will output [1,2]? ()A、 Set set = new TreeSet();B、 Set set = new HashSet();C、 Set set = new SortedSet();D、 List set = new SortedList();E、 Set set = new LinkedHashSet();

考题 1. public class enclosingone (  2. public class insideone{}  3. )  4. public class inertest(  5. public static void main (string[]args)(  6. enclosingone eo= new enclosingone ();  7. //insert code here  8. )  9. )    Which statement at line 7 constructs an instance of the inner class?()  A、 InsideOnew ei= eo.new InsideOn();B、 Eo.InsideOne ei = eo.new InsideOne();C、 InsideOne ei = EnclosingOne.new InsideOne();D、 EnclosingOne.InsideOne ei = eo.new InsideOne();

考题 现有:  1. interface Animal {  2. void eat();  3. }  4.  5. // insert code here  6.  7. public class HouseCat extends Feline {  8. public void eat() { }  9. }   和五个声明:  abstract class Feline implements Animal { }  abstract class Feline implements Animal { void eat(); }  abstract class Feline implements Animal { public void eat(); }  abstract class Feline implements Animal { public void eat() { } }  abstract class Feline implements Animal { abstract public void eat(); }  分别插入到第5行,有几个可以通过编译?() A、0B、1C、2D、3

考题 1. import java.util.*;  2.  3. Class FindStuff {  4. public static void  main(String [] args) {  5. // insert code here  6. c.put("x", 123);  7. }  8. } 分别插入到第5行,哪三行允许代码编译?() A、Map c = new SortedMap();B、HashMap c = new HashMap();C、HashMap c = new Hashtable();D、SortedMap c = new TreeMap();

考题 现有:   1. interface Animal {    2.   void eat();   3.  }    4.   5. // insert code here    6.   7. public class HouseCat implements Feline {    8.   public void eat() { }   9. }   和以下三个接口声明:   interface Feline extends Animal { }    interface Feline extends Animal { void eat(); }     interface Feline extends Animal { void eat() { } }    分别插入到第 5 行,有多少行可以编译?()  A、 0B、 1C、 2D、 3

考题 多选题Given: 10. interface Jumper { public void jump(); } ...   20. class Animal {} ...   30. class Dog extends Animal {   31. Tail tail;   32. }   ...   40. class Beagle extends Dog implements Jumper{   41. public void jump() {}  42. }   ...   50. class Cat implements Jumper{   51. public void jump() {}   52. }. Which three are true?()ACat is-a JumperBCat is-a AnimalCDog is-a JumperDDog is-a AnimalEBeagle has-a JumperFCat has-a AnimalGBeagle has-a Tail

考题 单选题interface Animal {  void soundOff();  }  class Elephant implements Animal {  public void soundOff() {  System.out.println(“Trumpet”);  }  }  class Lion implements Animal {  public void soundOff() { System.out.println(“Roar”);  }  }  class Alpha1 {  static Animal get( String choice ) {  if ( choice.equalsIgnoreCase( “meat eater” )) {  return new Lion();  } else {  return new Elephant();  }  }  }  Which compiles?()A  new Animal().soundOff();B  Elephant e = new Alpha1();C  Lion 1 = Alpha.get(“meat eater”);D  new Alpha1().get(“veggie”).soundOff();

考题 单选题1. import java.util.*;  2. public class Example {  3. public static void main(String[] args) {  4. // insert code here  5. set.add(new integer(2));  6. set.add(new integer(l));  7. System.out.println(set);  8. }  9. }  Which code, inserted at line 4, guarantees that this program will output [1,2]? ()A  Set set = new TreeSet();B  Set set = new HashSet();C  Set set = new SortedSet();D  List set = new SortedList();E  Set set = new LinkedHashSet();

考题 单选题11. class Animal { public String noise() { return “peep”; } }  12. class Dog extends Animal {  13. public String noise() { return “bark”; }  14. }  15. class Cat extends Animal {  16. public String noise() { return “meow”; }  17. }  .....  30. Animal animal = new Dog();  31. Cat cat = (Cat)animal;  32. System.out.printIn(cat.noise());  What is the result?()A  peepB  barkC  meowD  Compilation fails.E  An exception is thrown at runtime.

考题 单选题现有:   1. interface Animal {    2.   void eat();   3.  }    4.   5. // insert code here    6.   7. public class HouseCat implements Feline {    8.   public void eat() { }   9. }   和以下三个接口声明:   interface Feline extends Animal { }    interface Feline extends Animal { void eat(); }     interface Feline extends Animal { void eat() { } }    分别插入到第 5 行,有多少行可以编译?()A  0B  1C  2D  3

考题 单选题1. public class enclosingone (  2. public class insideone{}  3. )  4. public class inertest(  5. public static void main (string[]args)(  6. enclosingone eo= new enclosingone ();  7. //insert code here  8. )  9. )    Which statement at line 7 constructs an instance of the inner class?()A  InsideOnew ei= eo.new InsideOn();B  Eo.InsideOne ei = eo.new InsideOne();C  InsideOne ei = EnclosingOne.new InsideOne();D  EnclosingOne.InsideOne ei = eo.new InsideOne();

考题 多选题10. interface Jumper { public void jump(); }  ......  20. class Animal {}  ......  30. class Dog extends Animal { 31. Tail tail; 32. }  ......  40. class Beagle extends Dog implements Jumper {  41. public void jump() { }  42. }  .......  50. class Cat implements Jumper {  51. public void jump() { }  52. }  Which three are true?()ACat is-a AnimalBCat is-a JumperCDog is-a AnimalDDog is-a JumperECat has-a AnimalFBeagle has-a TailGBeagle has-a Jumper

考题 单选题1. public class A {  2. void A() {  3. System.out.println(“Class A”);  4. }  5. public static void main(String[] args) {  6. new A();  7. }  8. }  What is the result?()A  Class AB  Compilation fails.C  An exception is thrown at line 2.D  An exception is thrown at line 6.E  The code executes with no output.