试验五 JAVA 程序设计.doc

实验五 继承与多态专业班级学 号姓 名实验学时2实验类型验证性实验地点软件工程实验室实验时间指导老师曹记东实验成绩 年 月 日一、实验目的：理解继承与多态的概念，掌握三种访问控制的区别，掌握抽象类、接口与包的应用。二、实验内容：1. 参考教材P112，示例程序C5_17，掌握抽象类的应用。2. 参考教材P116，示例程序C5_19，掌握接口的使用方法。3. 参考教材P121，示例程序C5_20，掌握包的使用方法。三、实验要求：1.完成示例程序的验证。2.写出实验报告。四、实验步骤与结果：（由学生按照实验内容完成）程序如下程序1.package d; import java.awt.*;import java.applet.*;abstract class Shapes /定义一个抽象类Shapes public int x,y; /x、y为画图的坐标 public int width,height; public Shapes(int x,int y,int width,int height) this.x=x; this.y=y; this.width=width; this.height=height; abstract double getArea();/求图形面积的抽象方法 abstract double getPerimeter();/求图形周长的抽象方法class Square extends Shapes /由抽象类Shapes派生的子类矩形类 public double getArea()return(width*height); public double getPerimeter()return(2*width+2*height); public Square(int x,int y,int width,int height) super(x,y,width,height); class Triangle extends Shapes /由抽象类Shapes派生的子类三角形类 public double c;/斜边 public double getArea()return(0.5*width*height); public double getPerimeter()return(width+height+c); public Triangle(int x,int y,int base,int height) super(x,y,base,height); c=Math.sqrt(width*width+height*height); class Circle extends Shapes /由抽象类Shapes派生的子类圆类 public double r;/半径 public double getArea()return(r*r*Math.PI); public double getPerimeter()return(2*Math.PI*r); public Circle(int x,int y,int width,int height) super(x,y,width,height); r=(double)width/2.0; public class Q extends Applet Square Box=new Square(5,15,25,25); Triangle tri=new Triangle(5,50,8,4); Circle Oval=new Circle(5,90,25,25); public void paint(Graphics g) /画正方形 g.drawRect(Box.x,Box.y,Box.width,Box.height); g.drawString(Box Area:+Box.getArea(),50,35); g.drawString(Box Perimeter:+Box.getPerimeter(),50,55); g.drawString(tri Area:+tri.getArea(),50,75); g.drawString(tri Perimeter:+tri.getPerimeter(),50,95); /画圆 g.drawOval(Oval.x,Oval.y,Oval.width,Oval.height); g.drawString(oval Area:+Oval.getArea(),50,115); 运行结果 程序2.package cc;import java.awt.*;import java.applet.*;interface Shapes abstract double getArea(); abstract double getPerimeter();class Coordinates int x,y; public Coordinates(int x,int y) this.x=x; this.y=y; /Square Coordinates Shapesclass Square extends Coordinates implements Shapes public int width,height; public double getArea()return(width*height); public double getPerimeter()return(2*width+2*height); public Square(int x,int y,int width,int height) super(x,y); this.width=width; this.height=height; class Triangle extends Coordinates implements Shapes public int width,height; public double c; public double getArea()return(0.5*width*height); public double getPerimeter()return(width+height+c); public Triangle(int x,int y,int base,int height) super(x,y); width=base; this.height=height; c=Math.sqrt(width*width+height*height); class Circle extends Coordinates implements Shapes public int width,height; public double r; public double getArea()return(r*r*Math.PI); public double getPerimeter()return(2*Math.PI*r); public Circle(int x,int y,int width,int height) super(x,y); this.width=width; this.height=height; r=(double)width/2.0; public class D extends Applet Square Box=new Square(5,15,25,25); Triangle tri=new Triangle(5,50,8,4); Circle Oval=new Circle(5,90,25,25); public void paint(Graphics g) g.drawRect(Box.x,Box.y,Box.width,Box.height); g.drawString(Box Area:+Box.getArea(),50,35); g.drawString(Box Perimeter:+Box.getPerimeter(),50,55); g.drawString(tri Area:+tri.getArea(