c类是a类的引用类，当C 类指向B类是可以调用B类从A类继承方法和变量，但不能调用，B类新增的方法和变量

class DuiXiang1 extends DuiXiang{
String eadder;
void print(){
System.out.println("住址"+eadder);
}

}

public class DuiXiang{
String ename;
int eid;
int eage;
public String eadder;
void print(){
System.out.println("姓名"+ename+"ID号"+eid+"年龄"+eage);
}
}
public class Text {
public static void main(String args[]){
DuiXiang a1=new DuiXiang1();
DuiXiang a2=new DuiXiang1();
a1.ename="wanger";
a1.eid=14;
a1.eage=22;
System.out.println("这是一个父类的引用指向子类的象");
a1.print();
a2.eadder="shanghaishi";
a2.print();
}


}