JAVA学习日报 7.17

在欺负去年C++课程中实验2的继承派生问题前，我认为该仔细研究一下JAVA里的继承原则

在这里简单地写了一个继承关系（dessert指甜点；Macaron指马卡龙）

class Dessert{
    public String[] teast= {"egg","Cake Flour"};
    private String steast= "suger";
}
class Macaron extends Dessert{
    public String[] extra={"milk","almond powder"};
    private String sextra="colorlip";
    public void cookbook(){
        System.out.print(teast+"\n"+steast+"\n");
    }
}

这里编译器报错，错误内容如下：

字段Dessert.steast不可见

那么这里我们就可以知道，和C++相同，子类确实可以访问父类的公有成员，但不能访问其私有成员

我们再派生一个抹茶马卡龙（Matcharon）类：

class Matcharon extends Macaron{
    String[] nextextra= {"Matcha","tea leaf"};
    public void cookbook3(){
        System.out.print(teast[0]+" "+teast[1]+"\n");
        System.out.print(nextextra[0]+" "+nextextra[1]+"\n");
    }

没有报错，所以JAVA里的继承关系完全是可传递的

最终程序代码如下：

package test;
class Dessert{
    public String[] teast= {"egg","Cake Flour"};
    private String steast= "suger";
    public void cookbook1(){
        System.out.print(steast+"\n");
    }
}
class Macaron extends Dessert{
    public String[] extra={"milk","almond powder"};
    private String sextra="colorlip";
    public void cookbook2(){
        System.out.print(teast[0]+" "+teast[1]+"\n");
        System.out.print(sextra+"\n");
    }
}
class Matcharon extends Macaron{
    String[] nextextra= {"Matcha","tea leaf"};
    public void cookbook3(){
        System.out.print(teast[0]+" "+teast[1]+"\n");
        System.out.print(nextextra[0]+" "+nextextra[1]+"\n");
    }
}

public class test1 {

    public static void main(String[] args) {
        Matcharon o=new Matcharon();
        o.cookbook1();
        o.cookbook2();
        o.cookbook3();
    }

}

运行结果为：

 

 期待明天摧残老作业（笑）