设计一个形状类Shape,方法:求周长和求面积

形状类的子类:Rect(矩形),Circle(圆形)

Rect类的子类:Square(正方形)

不同的子类会有不同的计算周长和面积的方法

创建三个不同的形状对象,放在Shape类型的数组里,分别打印出每个对象的周长和面积

package day0419;

public abstract class Shape {

public abstract double getZhouChang();

public abstract double getMianJi();

}

package day0419;

public class Rect extends Shape {

private double length;

private double width;

// 构造方法

public Rect(double length, double width)

{

this.length = length;

this.width = width;

}

public Rect() {

}

public double getZhouChang() {

return (length + width) *

2;

}

public double getMianJi() {

return length * width;

}

public double getLength() {

return length;

}

public double getWidth() {

return width;

}

public void setLength(double length) {

this.length = length;

}

public void setWidth(double width) {

this.width = width;

}

}

package day0419;

public class Circle extends Shape {

private double banjing;

public Circle(double banjing) {

this.banjing = banjing;

}

public Circle(){

}

public double getBanJing() {

return banjing;

}

public void setBanJing(double banjing) {

this.banjing = banjing;

}

public double getZhouChang() {

return Math.PI*banjing*2;

}

public double getMianJi() {

return

Math.PI*banjing*banjing;

}

}

package day0419;

public class Square extends Rect {

public Square(double len) {

// 调用父类构造方法

super (len,len);

}

public Square() {

super ();

}

}

package day0419;

public class ShapeTest {

public static void main(String args[]) {

Shape[] ss = new

Shape[3];

Rect r = new Rect();

r.setLength(3);

r.setWidth(2);

// ss[0] = new Rect(3,2);

ss[0] = r;

ss[1] = new Circle(2);

ss[2] = new Square(4);

for (int i = 0; i

< ss.length; i++) {

System.out.println(ss[i].getZhouChang());

System.out.println(ss[i].getMianJi());

}

}

}