2020.8.14

一、今日学习内容

   1、研究生继承

public class Student2 {
    protected int num;
    protected String name;
    protected char sex;
    Student2(){}
    public void setValue(int n,String str,char c) {
        num=n;
        name=str;
        sex=c;
    }
    public void display() {
        System.out.println("学号:"+num+"	 姓名:"+name+"	 性别:"+sex);
    }
}
public class Postgraduent1 extends Student2 {
    private String advisor;
    Postgraduent1(){}
    public void setAdvisor(String str) {
        advisor=str;
    }
    public static void main(String[] args) {
        Postgraduent1 xq=new Postgraduent1();
        xq.setValue(1122, "Xiao Qiang", 'M');
        xq.setAdvisor("Prof.Zhu");
        xq.display();
        System.out.println("Advisor:"+xq.advisor);
    }
}

     

   2、多边形继承

//父类：
public class CPolygon {
    protected int width,height;
    public void setValues(int a,int b)
    {
        width=a;
        height=b;
    }
}
//子类1：长方形
public class CRectangle extends CPolygon {
    public int area() {
        return width*height;
    }
}
//子类2：三角形
public class CTriangle extends CPolygon {
    public int area() {
        return (width*height)/2;
    }
}
//实现类：
public class main1 {
    public static void main(String[] args) {
        CRectangle rect=new CRectangle();
        CTriangle trgl=new CTriangle();
        rect.setValues(4, 5);
        trgl.setValues(4, 5);
        System.out.println("长方形面积:"+rect.area());
        System.out.println("三角形面积:"+trgl.area());
    }
}

   

  3、日期时间类

//接口1：日期
public interface Date {
    public void setDate(int y,int mo,int d);
    public void displayDate();
}
//接口2：时间
public interface Time {
    public void setTime(int h,int mi,int s);
    public void displayTime();
}
//实现类：
public class Datetime implements Date,Time {
    protected int year,month,day,hour,minute,second;
    public void setDate(int y,int mo,int d) {
        year=y;
        month=mo;
        day=d;
    }
    public void displayDate() {
        System.out.println(year+"-"+month+"-"+day);
    }
    public void setTime(int h,int mi,int s) {
        hour=h;
        minute=mi;
        second=s;
    }
    public void displayTime() {
        System.out.println(hour+":"+minute+":"+second);
    }
    public static void main(String[] args) {
        Datetime dt=new Datetime();
        dt.setDate(2020, 5, 20);
        dt.setTime(20, 13,14);
        dt.displayDate();
        dt.displayTime();
    }
}

   

  4、研究生继承2

//父类：学生类
public class Student2 {
    protected int num;
    protected String name;
    protected char sex;
    Student2(){}
    Student2(int n,String str,char c) {
        num=n;
        name=str;
        sex=c;
    }
    public void display() {
        System.out.println("学号:"+num+"	姓名:"+name+"	 性别:"+sex);
    }
}
//子类：研究生类
public class Postgraduent1 extends Student2 {
    private String advisor;
    Postgraduent1(){}
    Postgraduent1(int n,String s,char c,String str){
        super(n,s,c);
        advisor=str;
    }
    public static void main(String[] args) {
        Postgraduent1 xq=new Postgraduent1(10001, "小明", 'M',"Prof.Zhu");
        xq.display();
        System.out.println("Advisor:"+xq.advisor);
    }
}

   

二、遇到的问题

    对接口在可以实现多继承方面不太了解，同时对继承的子类的构造函数不会写

三、明日计划

   继续完成相关例题