[Java]_ch11.3_階層類別庫設計

[Java]_ch11.3_階層類別庫設計

package Gjun.Taipei;

public class CCircle{

protected double pi=3.14;

protected double radius;

public CCircle(){

radius=1.0;

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

}

public CCircle(double r){

radius=r;

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

}

public final void show() {

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

}

}



package Gjun.Hsinchu;

import Gjun.Taipei.CCircle;

public class CCoin extends CCircle{

int value;

public CCoin(){

// super(1);

value=5;

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

}

public CCoin(double v){

super(v);

value=(int)v;

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

}

public void setValue(int v) {

value=v;

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

}

// void show() {

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

// }

public String toString() {

String data="物件內容: radius="+radius+" pi="+pi+" value="+value;

return data;

}

}

package Gjun;

import Gjun.Taipei.CCircle;

import Gjun.Hsinchu.*;

//import Gjun.*;

public class A9 {

public static void main(String[] args) {

CCircle c1=new CCircle();

c1.show();

// c1.setValue(999);

CCoin c2=new CCoin();

c2.show();

c2.setValue(100);

CCircle c3=new CCoin(4.0);

c3.show();

// c3.setValue(50);

CCoin c4=(CCoin) c3;

}

}