public class Student {
    int id;//学号
    String name;//姓名
    double mathGrades;//数学成绩啊
    double computerGrades;//计算机成绩
    public Student(int id,String name,double mathGrades,double computerGrades){//构造方法
        this.id = id ;
        this.name = name;
        this.mathGrades = mathGrades;
        this.computerGrades = computerGrades ;
    }
    int getId(){//获取id
        return id;
    }
    void setId(int a){//修改id
        id = a;
    }
    String getName(){//获取name
        return name;
    }
    void setId(String b){//修改name
        name = b;
    }
    double getMathGrades(){//获取mathGrades
        return mathGrades;
    }
    void setMathGrades(double c){//修改mathGrades
        mathGrades = c;
    }
    double getComputerGrades(){//获取computerGrades
        return computerGrades;
    }
    void setComputerGrades(double d){//修改computerGrades
        computerGrades = d ;
    }
    void print (){
        System.out.println("学号:"+this.getId());
        System.out.println("姓名:"+this.getName());
        System.out.println("数学成绩:"+this.getMathGrades());
        System.out.println("计算机成绩:"+this.getComputerGrades());
    }
}
class PostGradute extends Student{
    String mentor;//导师
    String researchDirection;//研究方向

    public PostGradute(int id, String name, double mathGrades, double computerGrades) {
        //继承父类的构造方法
        super(id, name, mathGrades, computerGrades);
    }

    String getMentor(){//获取mentor
        return mentor;
    }
    void setMentor(String e){//修改mentor
        mentor =e ;
    }
    String getResearchDirection(){//获取researchDirection
        return  researchDirection;
    }
    void setResearchDirection(String f){//修改researchDirection
        researchDirection = f ;
    }
    void print (){
        System.out.println("学号:"+this.getId());
        System.out.println("姓名:"+this.getName());
        System.out.println("数学成绩:"+this.getMathGrades());
        System.out.println("计算机成绩:"+this.getComputerGrades());
        System.out.println("导师："+this.getMentor());
        System.out.println("研究方向："+this.getResearchDirection());
    }

    public static void main(String[] args) {
        Student st = new Student(20143240,"李四",65.5,75);
        st.print();
        PostGradute pg = new PostGradute(20143240,"李四",65.3,70);
        pg.print();
    }