摘要:
package zuoye2; public class People { protected double height; protected double weight; private String guojia; public double getHeight() { return height; } public void setHeight(double he... 阅读全文
摘要:
写一个father类,里面有两个属性和一个work方法,输出一句话。一个father的子类son重写work方法,并且还自己有一个sing方法用向上转型和向下转型测试 阅读全文