继承和多态实验报告

1、 实验项目名称 ： 继承和多态 （所属课程： Java语言程序设计 ）院 系： 专业班级： 姓 名：学号： 实验地点： 指导老师：本实验项目成绩： 教师签字： 日期： 1实验目的 （1）掌握类的继承机制。（2）熟悉类中成员变量和方法的访问控制。（3）熟悉方法或构造方法多态性。2.实验内容（1）模拟编写程序，理解类的继承、多态、继承和多态规则。（2）独立编程，实现类的继承和多态。3.实验作业设计一个类Shape（图形）包含求面积和周长的area()方法和perimeter()方法以及设置颜色的方法SetColor()，并利用Java多态技术设计其子类Circle（圆形）类、Rectangle（矩

2、形）类和Triangle（三角形）类，并分别实现相应的求面积和求周长的方法。每个类都要覆盖toString方法。海伦公式：三角形的面积等于s(s-a)(s-b)(s-c)的开方，其中s=(a+b+c)/2程序代码为：Class包package Class;public class Shape private String color = "while"public Shape(String color)this.color = color;public void setColor(String color)this.color = color;public String g

3、etColor()return color;public double getArea()return 0;public double getPerimeter()return 0;public String toString()return "color:" + color;package Class;public class Circle extends Shape private double radius;public Circle(String color,double radius) super(color);this.radius = radius;publi

4、c void setRadius(double radius)this.radius = radius;public double getRadius()return radius;public double getCircleArea()return 3.14*radius*radius;public double getCirclePerimeter()return 3.14*2*radius;public String toString() return "The Area is:" + getCircleArea() + "nThe Perimeter i

5、s:" + getCirclePerimeter();package Class;public class Rectangle extends Shapeprivate double width;private double height;public Rectangle(String color,double width,double height) super(color);this.width = width;this.height = height;public void setWidth(double width)this.width = width;public doub

6、le getWidth()return width;public void setHeight(double height)this.height = height;public double getHeight()return height;public double getRectangleArea()return width*height;public double getRectanglePerimeter()return 2*(width + height);public String toString()return "The Area is:" + getRe

7、ctangleArea() + "nThe Perimeter is:" + getRectanglePerimeter();package Class;public class Triangle extends Shapeprivate double a;private double b;private double c;private double s;public Triangle(String color,double a,double b,double c, double s)super(color);this.a = a;this.b = b;this.c =

8、c;this.s = s;public void setA(double a)this.a = a;public double getA()return a;public void setB(double b)this.b = b;public double getB()return b;public void setC(double c)this.c = c;public double getC()return c;public double getTriangleArea()return Math.sqrt(s*(s-a)*(s-b)*(s-c);public double getTria

9、nglePerimeter()return a + b + c;public String toString()return "The Area is:" + getTriangleArea() + "nThe Perimeter is:" + getTrianglePerimeter();Main包package Main;import Class.Shape;import Class.Circle;import Class.Rectangle;import Class.Triangle;import java.util.Scanner;public

10、class test public static void main(String args) Scanner input = new Scanner(System.in);System.out.print("请输入圆的半径： ");double radius = input.nextDouble();Circle circle = new Circle(null, radius);System.out.println(circle.toString(); System.out.print("n请输入矩形的宽： "); double width = in

11、put.nextDouble(); System.out.print("请输入矩形的高： "); double height = input.nextDouble();Rectangle rectangle = new Rectangle(null, width, height);System.out.println(rectangle.toString(); System.out.print("n请输入三角形的第一条边 a： "); double a = input.nextDouble(); System.out.print("请输入三角形的第二条边 b： "); double b = input.nextDouble(); System.out.print("请输入三角形的第三条边 c： "); double c = input.nextDouble(); doub