程序代码：

package ch4;

import java.sql.Date;
class Person{
    int pid;
    Date birthday;
    String address;
    String name;
    boolean sex;
    Person(){
        pid=-1;
        name=null;
        sex=false;
        address=null;
    }
   
    Person(int pid,String name,boolean sex,Date birthday,String address){
        this.pid=pid;
        this.name=name;
        this.sex=sex;
        this.address=address;
    }
    public void setPoint(int x,boolean y){
    pid=x;
    sex=y;
        System.out.println(pid);
        if (sex) System.out.println("男");
        else
            System.out.println("女");
    }
}
class Student extends Person{
    int sno;
    String school;
    Student(){
        super();
        sno=-1;
        school=null;
    }
    Student(int pid,String name,boolean sex,Date birthday,String address,int sno,String school){
        super(pid,name,sex,birthday,address);
        this.sno=sno;
        this.school=school;
    }
    void printData(){
        System.out.println("姓名："+name);
        System.out.println("学校："+school);
        System.out.println("学号："+sno);
    }
}
public class Ex4_7 {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
  Person p=new Person();
  p.setPoint(100,true);
  Student t=new Student(11111,"陆嘉文",true,19900125,"金溪县",31,"电力职院");
  t.printData();
    }
}


这是JAVA的代码，请问我错在哪里啊！eclipse它是说我的Student够着函数没有定义，请问是怎么回事呢？