Description
定义一个形状类Shape，提供计算周长getPerimeter()和面积getArea()的函数
定义一个子类正方形类Square继承自Shape类，拥有边长属性，提供构造函数，能够计算周长getPerimeter()和面积getArea()
定义一个子类长方形类Rectangle继承自Square类，拥有长、宽属性，提供构造函数，能够计算周长getPerimeter()和面积getArea()
定义一个子类圆形类Circle继承自Shape，拥有半径属性，提供构造函数，能够计算周长getPerimeter()和面积getArea()
在main函数中，分别构造三个子类的对象，并输出他们的周长、面积.
Input
正方形类的边长
长方形类的长宽
圆类的半径
Output
正方形的周长、面积
长方形的周长、面积
圆形的周长、面积
Sample Input
1
1 2
2
Sample Output
4.00 1.00
6.00 2.00
12.57 12.57
HINT
用System.out.printf("%.2f",d)进行格式化输出
import java.util.Scanner;
public class Main{
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
double length = scan.nextDouble();
Square s = new Square(length);
System.out.printf("%.2f ",s.getPerimeter());
System.out.printf("%.2f\n",s.getArea());
length = scan.nextDouble();
double wide = scan.nextDouble();
Rectangle r = new Rectangle(length,wide);
System.out.printf("%.2f ",r.getPerimeter());
System.out.printf("%.2f\n",r.getArea());
double radius = scan.nextDouble();
Circle c = new Circle(radius);
System.out.printf("%.2f ",c.getPerimeter());
System.out.printf("%.2f\n",c.getArea());
scan.close();
}
}
abstract class Shape{
public abstract double getArea();
public abstract double getPerimeter();
}
class Square extends Shape{
private double length;
public Square(double length)
{
this.length = length;
}
public double getArea()
{
return length*length;
}
public double getPerimeter()
{
return 4 * length;
}
}
class Rectangle extends Square{
private double length;
private double wide;
public Rectangle(double length,double wide)
{
super(length);
this.length = length;
this.wide = wide;
}
public double getArea()
{
return length*wide;
}
public double getPerimeter()
{
return (length+wide)*2;
}
}
class Circle extends Shape{
private double radius;
public Circle(double radius)
{
this.radius = radius;
}
public double getArea()
{
return 3.1415926*radius*radius;
}
public double getPerimeter()
{
return 3.1415926*2*radius;
}
}