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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
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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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有如下程序: include using namespaee std;class Animal{ public: virtual char*g
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( 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 】 。
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1. Everyone in our class ________ .A. like singingB. likes play footballC. like watch TVD. likes playing games
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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【 】
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下列程序片段中,能通过编译的是( )。 A.public abstract class Animal{ public void speak;}S
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1. public class Target { 2. private int i = 0; 3. public int addOne() { 4. return ++i; 5. } 6. } And: 1. public class Client { 2. public static void main(String[] args) { 3. System.out.println(new Target().addOne()); 4. } 5. } Which change can you make to Target without affecting Client?() A、 Line 4 of class Target can be changed to return i++;B、 Line 2 of class Target can be changed to private int i = 1;C、 Line 3 of class Target can be changed to private int addOne() {D、 Line 2 of class Target can be changed to private Integer i = 0;
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1. public interface A { 2. public void doSomething(String thing); 3. } 1. public class AImpl implements A { 2. public void doSomething(String msg) { } 3. } 1. public class B { 2. public A doit() { 3. // more code here 4. } 5. 6. public String execute() { 7. // more code here 8. } 9. } 1. public class C extends B { 2. public AImpl doit() { 3. // more code here 4. } 5. 6. public Object execute() { 7. // more code here 8. } 9. } Which statement is true about the classes and interfaces in the exhibit?() A、 Compilation will succeed for all classes and interfaces.B、 Compilation of class C will fail because of an error in line 2.C、 Compilation of class C will fail because of an error in line 6.D、 Compilation of class AImpl will fail because of an error in line 2.
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1. public class a { 2. public void method1() { 3. try { 4. B b=new b(); 5. b.method2(); 6. // more code here 7. } catch (TestException te) { 8. throw new RuntimeException(te); 9. } 10. } 11. } 1. public class b { 2. public void method2() throws TestException { 3. // more code here 4. } 5. } 1. public class TestException extends Exception { 2. } Given: 31. public void method() { 32. A a=new a(); 33. a.method1(); 34. } Which is true if a TestException is thrown on line 3 of class b?()A、 Line 33 must be called within a try block.B、 The exception thrown by method1 in class a is not required to be caught.C、 The method declared on line 31 must be declared to throw a RuntimeException.D、 On line 5 of class a, the call to method2 of class b does not need to be placed in a try/catch block.
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现自: 1. interface Color { } 2. interface Weight { } 3. //insert code here 和以下足六个声明: class Boat extends Color, extends Weight { } class Boat extends Color and Weight { } class Boat extends Color, Weight { } class Boat implements Color, implements Weight { } class Boat implements Color and Weight { } class Boat implements Color, Weight { } 分别插入到第3行,有多少行可以编译? () A、 0B、 1C、 2D、 3
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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();
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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.
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Which two demonstrate an “is a” relationship?() A、 public interface Person { } public class Employee extends Person { }B、 public interface Shape { } public class Employee extends Shape { }C、 public interface Color { } public class Employee extends Color { }D、 public class Species { } public class Animal (private Species species;)E、 interface Component { } Class Container implements Component ( Private Component[ ]children; )
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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
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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
多选题Which three demonstrate an “is a” relationship?()Apublic class X { } public class Y extends X { }Bpublic interface Shape { } public interface Rectangle extends Shape{ }Cpublic interface Color { } public class Shape { private Color color; }Dpublic interface Species { } public class Animal { private Species species; }Epublic class Person { } public class Employee { public Employee(Person person) { }Finterface Component { } class Container implements Component { private Component[] children; }
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单选题在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
多选题Which two demonstrate an “is a” relationship?()Apublic interface Person { } public class Employee extends Person { }Bpublic interface Shape { } public class Employee extends Shape { }Cpublic interface Color { } public class Employee extends Color { }Dpublic class Species { } public class Animal (private Species species;)Einterface Component { } Class Container implements Component ( Private Component[ ]children; )
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单选题现有: 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
多选题Which the two demonstrate an “is a” relationship?()Apublic interface Person {} Public class Employee extends Person {}Bpublic interface Shape {} public interface Rectangle extends Shape {}Cpublic interface Color {} public class Shape { private Color color; }Dpublic class Species {} public class Animal { private Species species; }Einterface Component {} Class Container implements Component {private Component [] children;
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
单选题现有: 1. interface Animal f 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
单选题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. 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
考题
单选题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
单选题In a class of 160 seniors, the ratio of boys to girls is 3 to 5. In the junior class, the ratio of boys to girls is 3 to 2. When the two classes are combined, the ratio of boys to girls is 1 to 1. How many students are in the junior class?A
400B
360C
200D
180E
160
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