java一个程序中有不同的类_编写一个java程序，除了主类外，该程序中还有2两个类：People和ChinaPeople。...

eople和ChinaPeople。People类有访问权限是protected的double类型成员变量height和weight，以及publicvoidspeakHello()、publicvoidaverageHeight()和publicvoidaverageWeight()方法。...

eople和ChinaPeople。People类有访问权限是protected的double类型成员变量height和weight，以及public void speakHello()、public void averageHeight()和public void averageWeight()方法。 ChinaPeople类是People类的子类，新增了public void chinaGongfu()方法。要求ChinaPeople重写父类的public void speakHello()方法。

具体的步骤如下：

1)定义People类。

class People{

protected double height,weight;

public void speakHello(){System.out.println(“hello”);}

public void averageHeight(){System.out.println(height);}

public void averageWeight(){System.out.println(weight);}

}

2)定义ChinaPeople类。

class ChinaPeople extends People{

public void speakHello(){System.out.println(“大家好!”);}

}

3)定义主类如下：

public class ShiYan_2{

public static void main(String r[]){

ChinaPeople cp=new ChinaPeople();

cp.speakHello(); cp.averageHeight();

People p=new ChinaPeople();

p.speakHello(); p.averageHeight();

}

}

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