java11月13日

java 定义一个图形类及其子类（三角形类和矩形类），分别计算其面积和周长。

package ListSixTen;

abstract class Shape {

public abstract double area();

public abstract double perimeter();

}

 

package ListSixTen;

class Rectangle extends Shape{   //矩形

private double wide;         //宽

private double longs;        //长

public Rectangle(){

}

public Rectangle(double wide,double longs){

super();

this.wide=wide;

this.longs=longs;

}

public void setWide(double wide){

this.wide=wide;

}

public double getWide(){

return wide;

}

public void setLongs(double longs){

this.longs=longs;

}

public double longs(){

return longs;

}

public double area() {

return this.longs*this.wide;

}

public double perimeter() {

return (this.longs+this.wide)*2;

}

}

 

package ListSixTen;

class Triangle extends Shape {          //三角形

private double edgea;

private double edgeb;

private double edgec;

public Triangle(){}

public Triangle(double edgea,double edgeb,double edgec){

super();

this.edgea=edgea;

this.edgeb=edgeb;

this.edgec=edgec;

}

public double area(){

return this.edgea*this.edgeb/2;

}

public double perimeter(){

return this.edgea+this.edgeb+this.edgec;

}

public void setEdgea(double edgea){

this.edgea=edgea;

}

public double getEdgea(){

return edgea;

}

public void setEdgeb(double edgeb){

this.edgeb=edgeb;

}

public double getEdgeb(){

return edgeb;

}

public void setEdgec(double edgec){

this.edgec=edgec;

}

public double getEdgec(){

return edgec;

}

}

package ListSixTen;

public class TestDemo10 {

public static void main(String[] args) {

Shape rectangle = new Rectangle(10.5, 20.6);

Shape triangle = new Triangle(10.1, 20.2, 30.3);

Shape round = new Round(30.3) ;

System.out.println("矩形面积：" + rectangle.area() + "，矩形周长：" + rectangle.perimeter());

System.out.println("三角形面积：" + triangle.area() + "，三角形周长：" + triangle.perimeter());

}

}

结果：

矩形面积：216.3，矩形周长：62.2

三角形面积：102.00999999999999，三角形周长：60.599999999999994