子类会继承父类对于接口的实现

package exercise2;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

interface CircleShape {
double PI = 3.14159;

double area(double radius);
}

class Circle implements CircleShape {
int radius;

public Circle(int r) {
radius = r;
}

public double perimeter() {
return (2 * PI * radius);
}

@Override
public double area(double radius) {
return (PI * radius * radius);
}
}

class Cylinder extends Circle implements CircleShape {// 子类会继承父类对于接口的实现
int heigh;
int radius;

public Cylinder(int r, int h) {
super(r);
heigh = h;
}

public double baseAera(double radius) {
return area(radius);
}

public double area1(double radius) {
return (heigh * super.perimeter() + 2 * area(radius));
}

public double volume(double radius) {
return (heigh * area(radius));
}
}

public class Ex13_2 {
public static void main(String[] args) throws IOException {
int r1, r2;
String t;
System.out.println("请输入圆cir1和cir2的半径r1,r2");
BufferedReader scan = new BufferedReader(new InputStreamReader(
System.in));
t = scan.readLine();
r1 = Integer.parseInt(t);
t = scan.readLine();
r2 = Integer.parseInt(t);
Circle cir1 = new Circle(r1);
Circle cir2 = new Circle(r2);
System.out.println("圆cir1的面积是" + cir1.area(r1) + "\t周长是："
+ cir1.perimeter());
System.out.println("圆cir2的面积是" + cir1.area(r2) + "\t周长是："
+ cir2.perimeter());
int h1, h2;
System.out.println("请输入圆柱cy1的半径和高：");
t = scan.readLine();
r1 = Integer.parseInt(t);
t = scan.readLine();
h1 = Integer.parseInt(t);
Cylinder cy1 = new Cylinder(r1, h1);
System.out.println("cy1的底圆面积是：" + cy1.baseAera(r1));
System.out.println("cy1的体积是：" + cy1.volume(r1) + "\t表面积是："
+ cy1.area1(r1));

System.out.println("请输入圆柱cy2的半径和高：");
t = scan.readLine();
r2 = Integer.parseInt(t);
t = scan.readLine();
h2 = Integer.parseInt(t);
Cylinder cy2 = new Cylinder(r2, h2);
System.out.println("cy2的底圆面积是：" + cy2.baseAera(r1));
System.out.println("cy2的体积是：" + cy2.volume(r1) + "\t表面积是："
+ cy2.area1(r2));
}

}