public abstract class Shape {
public abstract void zhouChang();
public abstract void mianJi();}
public class Test {
public static void main(String[] args) {
//new一个矩形长4宽5
Shape a=new Rectangle(4,5);
a.zhouChang();
a.mianJi();
//new一个圆，半径为5
Shape b=new Circle(5);
b.zhouChang();
b.mianJi();
}}
public class Circle extends Shape {
int a;
final double P=3.14;
public Circle(int a) {
super();
this.a = a;}
DecimalFormat df = new DecimalFormat("###.00");
public void zhouChang(){
System.out.println("圆形的周长是"+df.format(2*a*P));
}
public void mianJi(){
System.out.println("圆形的面积是"+(a*a*P));
}
}
public class Rectangle extends Shape{
//a长b宽，构造方法赋值
int a;
int b;
public Rectangle(int a, int b) {
super();
this.a = a;
this.b = b;
}
public void zhouChang(){
System.out.println("矩形的周长是"+(a+b)*2);
}
public void mianJi(){
System.out.println("矩形的面积是"+a*b);
}
}
