[Java]_ch11.1_Package觀念介紹

[Java]_ch11.1_Package觀念介紹

package Gjun;

class CCircle{

protected double pi=3.14;

protected double radius;

CCircle(){

radius=1.0;

System.out.println("0.父類別建構元(), pi="+pi+" radius="+radius);

}

CCircle(double r){

radius=r;

System.out.println("1.父類別建構元(double r), pi="+pi+" radius="+radius);

}

final void show(){

System.out.println("父類別show(), pi="+pi+" radius="+radius+" area="+pi*radius*radius);

}

void setValue(int v){}

}





package Gjun;

class CCoin extends CCircle{

int value;

CCoin(){

      super(4.0);

value=5;

System.out.println("0.子類別建構元(), pi="+pi+" radius="+radius+" value="+value);

}

CCoin(double v){

value=(int)v;

System.out.println("1.子類別建構元(double v), pi="+pi+" radius="+radius+" value="+value);

}

void setValue(int v){

value=v;

System.out.println("子類別setValue(), value="+value+" pi="+pi+" radius="+radius);

}

// public void show(){

// System.out.println("子類別show(), pi="+pi+" radius="+radius+" area="+pi*radius*radius+" value="+value);

// }

}

package Gjun;

public class A9 {

public static void main(String[] args) {

CCircle c1=new CCircle(2.0);

c1.show();

// c1.setValue(50);

CCoin c2=new CCoin();

c2.setValue(100);

c2.show();

CCircle c3=new CCoin(99);

c3.show();

c3.setValue(88);

}

}