CQ3

super.bark(); 不要第一个括号

 

Write a concrete meow( ) method 抽象类实例化后要加一个实例化的方法。

抽象类里可以没有抽象方法。

 

What does it mean to say that inheritance hierarchies are coupled? Changes to the parent affect the child 父类的变化会影响子类

 

 

不对因为父类里没有constructor,必须要有

public class Snake {

   public int length;

   public Snake(int length) { this.length = length;}

}

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public class Boa extends Snake {

   public Boa( ) { this.length = 0;}

}