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单选题
下列程序的运行结果是(  )。class Shape{ public Shape(){ System.out.print("Shape"); }}class Circle extends Shape{ public Circle(){ System.out.print("Circle"); }}public class Test{ public static void main(String[]args){ Shape d=new Circle(); }}
A

Shape

B

Circle

C

ShapeCircle

D

程序有错误


参考答案

参考解析
解析:
继承是面向对象编程的一个主要优点之一,它对如何设计Java类有着直接的影响。该程序首先编写了一个Shape的类,然后又编写一个类Circle去继承Shape类。由于子类拥有父类所有的属性和方法,所以输出的是ShapeCircle。
更多 “单选题下列程序的运行结果是(  )。class Shape{ public Shape(){ System.out.print("Shape"); }}class Circle extends Shape{ public Circle(){ System.out.print("Circle"); }}public class Test{ public static void main(String[]args){ Shape d=new Circle(); }}A ShapeB CircleC ShapeCircleD 程序有错误” 相关考题
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考题 在Java语言中,如果你有下面的类定义:  Abstract class Shape{ Abstract void draw(); }  class Square extendeds Shape{} 如果你试图编译上面的代码会发生()。 A、一切成功编译B、Shape可以编译,Square不能编译C、Square可以编译,Shape不能编译D、Shape,Square都不能编译

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 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;

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 public abstract class Shape {  private int x;  private int y;  public abstract void draw();  public void setAnchor(int x, int y) {  this.x = x;  this.y = y;  }  }  Which two classes use the Shape class correctly?()A、 public class Circle implements Shape { private int radius; }B、 public abstract class Circle extends Shape { private int radius; }C、 public class Circle extends Shape { private int radius; public void draw(); }D、 public abstract class Circle implements Shape { private int radius; public void draw(); }E、 public class Circle extends Shape { private int radius;public void draw() {/* code here */} }F、 public abstract class Circle implements Shape { private int radius;public void draw() { / code here */ } }

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; }

考题 多选题public abstract class Shape {  private int x;  private int y;  public abstract void draw();  public void setAnchor(int x, int y) {  this.x = x;  this.y = y;  }  }  Which two classes use the Shape class correctly?()Apublic class Circle implements Shape { private int radius; }Bpublic abstract class Circle extends Shape { private int radius; }Cpublic class Circle extends Shape { private int radius; public void draw(); }Dpublic abstract class Circle implements Shape { private int radius; public void draw(); }Epublic class Circle extends Shape { private int radius;public void draw() {/* code here */} }Fpublic abstract class Circle implements Shape { private int radius;public void draw() { / code here */ } }

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;  )

考题 单选题public abstract class Shape {  int x;  int y;  public abstract void draw();  public void setAnchor(int x, int y) {  this.x = x;  this.y = y;  }  }  and a class Circle that extends and fully implements the Shape class. Which is correct?()A  Shape s = new Shape(); s.setAnchor(10,10); s.draw();B  Circle c = new Shape(); c.setAnchor(10,10); c.draw();C  Shape s = new Circle(); s.setAnchor(10,10); s.draw();D  Shape s = new Circle(); s-setAnchor(10,10); s-draw();E  Circle c = new Circle(); c.Shape.setAnchor(10,10); c.Shape.draw();

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;