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
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
相关考题:
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{ public abstract void speak();}D.public abstract class Animal{ public abstract void speak(){}}
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;}
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______。
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
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
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
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; }
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*/ } }
Which two allow the class Thing to be instantiated using new Thing()?A、 public class Thing { }B、 public class Thing { public Thing() {} }C、 public class Thing { public Thing(void) {} }D、 public class Thing { public Thing(String s) {} }E、 public class Thing { public void Thing() {} public Thing(String s) {} }
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
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
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
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*/} }
Which the two demonstrate an “is a” relationship?()A、 public interface Person {} Public class Employee extends Person {}B、 public interface Shape {} public interface Rectangle extends Shape {}C、 public interface Color {} public class Shape { private Color color; }D、 public class Species {} public class Animal { private Species species; }E、 interface Component {} Class Container implements Component {private Component [] children;
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; )
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
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
现有 public class Parentt public void change (int x){) ) public class Child extends Parent{ //覆盖父类change方法 } 下列哪个声明是正确的覆盖了父类的change方法?() A、 protected void change (int x){}B、 public void change(int x, int y){}C、 public void change (int x){}D、 public void change (String s){}
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
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
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?()APetp=(Pet)c运行错误BPetp=(Pet)c编译错误CPetp=(Pet)c止常执行D以上都不对
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
单选题现有: 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*/} }Bpublic class Employee extends Inf.implements Data{ public void load() {/*do something*/} }Cpublic class Empl.yee implements Inf extends Data{ public void Data.1oad(){* do something*/} public void load(){/*do something*/} }Dpublic class Employee extends Inf implements Data { public void Data.1oad() {/*do something*/) public void info.1oad(){/*do something*/} }
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?()APet Pet PetBCat Cat CatCCat Dog PetDCat Dog Dog
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?APet p = (Pet)c正常执行BPet p = (Pet)c编译错误CPet p = (Pet)c运行错误D以上都不对
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
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
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:()A1B2C3D4