[Java]_ch9.1_繼承觀念

class CCircle{

double pi=3.14;

double radius;

public CCircle(){

radius=1.0;

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

}

public CCircle(double r){

radius=r;

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

}

public void show(){

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

}

}

class CCoin extends CCircle{

int value;

public CCoin(){

      super(4.0);

value=5;

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

}

public CCoin(double v){

value=(int)v;

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

}

public void setValue(int v){

value=v;

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

}

}

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();

CCoin c3=new CCoin(99);



}



}