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单选题
现有:   public class Pet()  public class Cat extends Pet{)      执行代码  Cat c- new Cat();      Pet p=  (Pet)c;  后下列哪项是正确的?()
A

 Pet p=(Pet)c运行错误

B

 Pet p=(Pet)c编译错误

C

 Pet p= (Pet)c止常执行

D

以上都不对


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更多 “单选题现有:   public class Pet()  public class Cat extends Pet{)      执行代码  Cat c- new Cat();      Pet p=  (Pet)c;  后下列哪项是正确的?()A  Pet p=(Pet)c运行错误B  Pet p=(Pet)c编译错误C  Pet p= (Pet)c止常执行D 以上都不对” 相关考题
考题 如下程序的输出结果是______。 include using namespace std; class Pet{ char nam 如下程序的输出结果是______。include<iostream>using namespace std;class Pet{char name[10];public:Pet(char*nanle){strcpy(this->name,name);}const char*getName( )const{return name;}virtual void call( )eonst=0;};class Dog:public Pet{public:Dog(char*name):Pet(name){ }void call( )eonst{cout<<"汪汪叫";}};class Cat:public Pet{public:Cat(char*name):Pet(name){ }void call( )const{eout<<"喵喵叫";}};int main( ){Pet*petl=new Dog("哈克"),*pet2=new Cat("吉米");eout<<petl->getName( );petl->call( );eout<<endl;cout<<pet2->getName( );pet2->call( );eout<<endl;return 0;}

考题 Given:Which two, inserted at line 11, will allow the code to compile?() A.public class MinMax? {B.public class MinMax? extends Number {C.public class MinMaxN extends Object {D.public class MinMaxN extends Number {E.public class MinMax? extends Object {F.public class MinMaxN extends Integer {

考题 有如下程序: include using namespace std; class Pet{ char name[10]; public: Pet(c 有如下程序:include<iostream>using namespace std;class Pet{char name[10];public:Pet(char*name){strcpy(this->name,name);}const char*getName()const {return name;}virtual void call()const=0;};class Dog:public Pet{public:Dog(char*name):Pet(name){}void call()const{cout<<"汪汪叫":}};class Cat:public Pet{public:Cat(char*name):Pet(name){}void call()const{cout<<"喵喵叫";}};int main(){Pet*pet1=new Dog("哈克"),*pet2=new Cat("吉米");cout<<pet1->getName();pet1->call();cout<<end1;cout<<pet2->getName();pet2->call();cout<<end1;return 0;}程序的输出结果是______。

考题 public class Pet{     private String name;     public Pet(){  System.out.print(1);    }  public Pet(String name){        System.out.print(2);    } }  public class Dog extends Pet{     public Dog(String name){        System.out.print(3);    } }  执行new Dog(“棕熊”);后程序输出是哪项?() A、 23B、 13C、 123D、 321

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 public class Pet{     private String name;     public Pet(String name){       this.name = name;    }  public void speak(){     System.out.print(name); }  }  public class Dog extends Pet{     public Dog(String name){       super(name);    }  public void speak(){    super.speak();  System.out.print(“ Dog ”);    } }  执行代码   Pet pet = new Dog(“京巴”);  pet.speak();  后输出的内容是哪项?() A、 京巴B、 京巴 DogC、 nullD、 Dog京巴

考题 public class Pet{}  public class Cat extends Pet{}   执行代码   Cat c = new Cat();   Pet p = (Pet)c;   下列哪项是正确的? A、Pet p = (Pet)c正常执行B、Pet p = (Pet)c编译错误C、Pet p = (Pet)c运行错误D、以上都不对

考题 Which three demonstrate an “is a” relationship?() A、 public class X { }  public class Y extends X { }B、 public interface Shape { }  public interface Rectangle extends Shape{ }C、 public interface Color { }  public class Shape { private Color color; }D、 public interface Species { }  public class Animal { private Species species; }E、 public class Person { } public class Employee {  public Employee(Person person) { }F、 interface Component { }  class Container implements Component { private Component[] children; }

考题 interface Data { public void load(); }  abstract class Info { public abstract void load(); }  Which class correctly uses the Data interface and Info class?() A、 public class Employee extends Info implements Data { public void load() { /*do something*/ } }B、 public class Employee implements Info extends Data { public void load() { /*do something*/ } }C、 public class Employee extends Info implements Data { public void load() { /*do something */ } public void Info.load() { /*do something*/ } }D、 public class Employee implements Info extends Data { public void Data.load() { /*dsomething */ } public void load() { /*do something */ } }E、 public class Employee implements Info extends Data { public void load() { /*do something */ } public void Info.load(){ /*do something*/ } }F、 public class Employee extends Info implements Data{ public void Data.load() { /*do something*/ } public void Info.load() { /*do something*/ } }

考题 public class Pet{   private String name;   public Pet(){   System.out.print(1);  }   public Pet(String name){   System.out.print(2);  }   }   public class Dog extends Pet{  public Dog(String name){   //这里隐藏了一句代码:super.pet();   System.out.print(3);  }   }   执行new Dog(“棕熊”);后程序输出是哪项?() A、 23B、 1 3C、 123D、 321

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:   public class Pet()  public class Cat extends Pet{)      执行代码  Cat c- new Cat();      Pet p=  (Pet)c;  后下列哪项是正确的?()    A、 Pet p=(Pet)c运行错误B、 Pet p=(Pet)c编译错误C、 Pet p= (Pet)c止常执行D、以上都不对

考题 public class Pet{   private String name;   public Pet(){   System.out.print(1);  }   public Pet(String name){   System.out.print(2);   }  }   public class Dog extends Pet{  public Dog(){   System.out.print(4);  }   public Dog(String name){   //这里隐藏了一句代码:super.pet();   this();   System.out.print(3);  }  }   执行new Dog(“棕熊”);后程序输出是哪项?() A、 143B、 423C、 243D、 1134

考题 现有:  interface Data {public void load();}  abstract class Info {public abstract void load();}      下列类定义中正确使用Data和Info的是哪项?() A、 public class Employee implements Info extends Data { public void load(){/*dosomething*/}     }B、public class Employee extends Inf.implements Data{ public void load() {/*do something*/}     }C、public class Empl.yee implements Inf extends Data{ public void Data.1oad(){* do something*/}     public void load(){/*do something*/}     }D、public class Employee extends Inf implements Data  {  public void Data.1oad()  {/*do something*/)     public void info.1oad(){/*do something*/}    }

考题 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;  )

考题 What produces a compiler error?()  A、 class A { public A(int x) {} }B、 class A {} class B extends A { B() {} }C、 class A { A() {} } class B { public B() {} }D、 class Z { public Z(int) {} } class A extends Z {}

考题 public class Pet{  public void speak(){   System.out.print(“ Pet ”);  }  }   public class Cat extends Pet{  public void speak(){   System.out.print(“ Cat ”);  }  }   public class Dog extends Pet{  public void speak(){   System.out.print(“ Dog ”);  }  }   执行代码   Pet[] p = {new Cat(),new Dog(),new Pet()};   for(int i=0;i〈p.length;i++)   p[i].speak();   后输出的内容是哪项?()  A、Pet Pet PetB、Cat Cat CatC、Cat Dog PetD、Cat Dog Dog

考题 public class Pet{     private String name;     public Pet(){  System.out.print(1);    }  public Pet(String name){        System.out.print(2);    } }  public class Dog extends Pet{     public Dog(){  System.out.print(4);    }  public Dog(String name){        this();  System.out.print(3);    } }  执行new Dog(“棕熊”);后程序输出是哪项?()  A、 143B、 423C、 243D、 1134

考题 单选题public class Pet{   private String name;   public Pet(){   System.out.print(1);  }   public Pet(String name){   System.out.print(2);  }  }   public class Dog extends Pet{  public Dog(){   System.out.print(4);  }   public Dog(String name){   super(name);   System.out.print(3);  }   }   执行new Dog(“棕熊”);后程序输出是哪项?()A  33B  13C  23D  123

考题 单选题现有:   public class Pet()  public class Cat extends Pet{)      执行代码  Cat c- new Cat();      Pet p=  (Pet)c;  后下列哪项是正确的?()A  Pet p=(Pet)c运行错误B  Pet p=(Pet)c编译错误C  Pet p= (Pet)c止常执行D 以上都不对

考题 单选题现有: public class Pet( ) public class Cat extends Pet{) 执行代码 Cat c- new Cat( ); Pet p= (Pet)c; 后下列哪项是正确的?()A Petp=(Pet)c运行错误B Petp=(Pet)c编译错误C Petp=(Pet)c止常执行D 以上都不对

考题 单选题public class Pet{     private String name;     public Pet(){  System.out.print(1);    }  public Pet(String name){        System.out.print(2);    } }  public class Dog extends Pet{     public Dog(String name){        System.out.print(3);    } }  执行new Dog(“棕熊”);后程序输出是哪项?()A  23B  13C  123D  321

考题 单选题interface Data { public void load(); }  abstract class Info { public abstract void load(); }  Which class correctly uses the Data interface and Info class?()A  public class Employee extends Info implements Data { public void load() { /*do something*/ } }B  public class Employee implements Info extends Data { public void load() { /*do something*/ } }C  public class Employee extends Info implements Data { public void load() { /*do something */ } public void Info.load() { /*do something*/ } }D  public class Employee implements Info extends Data { public void Data.load() { /*dsomething */ } public void load() { /*do something */ } }E  public class Employee implements Info extends Data { public void load() { /*do something */ } public void Info.load(){ /*do something*/ } }F  public class Employee extends Info implements Data{ public void Data.load() { /*do something*/ } public void Info.load() { /*do something*/ } }

考题 单选题public class Pet{  public void speak(){   System.out.print(“ Pet ”);  }  }   public class Cat extends Pet{  public void speak(){   System.out.print(“ Cat ”);  }  }   public class Dog extends Pet{  public void speak(){   System.out.print(“ Dog ”);  }  }   执行代码   Pet[] p = {new Cat(),new Dog(),new Pet()};   for(int i=0;i〈p.length;i++)   p[i].speak();   后输出的内容是哪项?()A Pet Pet PetB Cat Cat CatC Cat Dog PetD Cat Dog Dog

考题 单选题public class Pet{}  public class Cat extends Pet{}   执行代码   Cat c = new Cat();   Pet p = (Pet)c;   下列哪项是正确的?A Pet p = (Pet)c正常执行B Pet p = (Pet)c编译错误C Pet p = (Pet)c运行错误D 以上都不对

考题 单选题public class Pet{   private String name;   public Pet(){   System.out.print(1);  }   public Pet(String name){   System.out.print(2);  }   }   public class Dog extends Pet{  public Dog(String name){   //这里隐藏了一句代码:super.pet();   System.out.print(3);  }   }   执行new Dog(“棕熊”);后程序输出是哪项?()A  23B  1 3C  123D  321

考题 单选题public class Pet{     private String name;     public Pet(String name){       this.name = name;    }  public void speak(){     System.out.print(name); }  }  public class Dog extends Pet{     public Dog(String name){       super(name);    }  public void speak(){    super.speak();  System.out.print(“ Dog ”);    } }  执行代码   Pet pet = new Dog(“京巴”);  pet.speak();  后输出的内容是哪项?()A  京巴B  京巴 DogC  nullD  Dog京巴

考题 单选题What produces a compiler error?()A  class A { public A(int x) {} }B  class A {} class B extends A { B() {} }C  class A { A() {} } class B { public B() {} }D  class Z { public Z(int) {} } class A extends Z {}