继承性的练习

package eightdemo;

/**
 * 1.(1)定义一个ManKind类，包括
 * 成员变量int sex和int salary；
 * 方法void manOrWorman()：根据sex的值显示“man”(sex==1)或者“women”(sex==0)；
 * 方法void employeed()：根据salary的值显示“no job”(salary==0)或者“ job”(salary!=0)。
 */
public class ManKind {
    private int sex;
    private int salary;

    public int getSex(){
        return sex;
    }
    public void setSex(int sex){
        this.sex = sex;
    }
    public int getSalary(){
        return salary;
    }
    public void setSalary(int salary){
        this.salary = salary;
    }

    public void manOrWomen(){
        if(sex == 1)
            System.out.println("Man");
        else if(sex == 0)
            System.out.println("Woman");
        else
            System.out.println("输入的数据有误");
    }
    public void employees(){
        if(salary == 0)
            System.out.println("no job");
        else if(salary > 0)
            System.out.println("job");
    }
}

package eightdemo;

/**
 * (2)定义类Kids继承ManKind，并包括
 * 成员变量int yearsOld；
 * 方法printAge()打印yearsOld的值。
 */
public class Kids extends ManKind {
    private int yearsOld;

    public int getYearsOld() {
        return yearsOld;
    }

    public void setYearsOld(int yearsOld) {
        this.yearsOld = yearsOld;
    }

    public void printAge() {
        System.out.println(this.yearsOld + "years old");
    }

    public void employees() {
        System.out.println("Kids should study and no job");
    }
}

package eightdemo;

/**
 * (3)在Kids类的main方法中实例化Kids的对象someKid，用该对象访问其父类的成员变量及方法。
 */
public class TestKids {
    public static void main(String[] args) {
        Kids someKid = new Kids();

        someKid.setSalary(0);
        someKid.setSex(1);
        someKid.setYearsOld(13);

        someKid.employees();
        someKid.manOrWomen();
        someKid.printAge();
    }
}

package eightdemo;

public class Circle {
    private double radius;

    public Circle(){
        this.radius = 1;
    }

    public double getRadius(){
        return radius;
    }
    public void setRadius(double radius){
        this.radius = radius;
    }

    //计算园的面积
    public double findArea(){
        return Math.PI * radius * radius;
    }
}

package eightdemo;

public class Cylinder extends Circle {
    private double length;//圆柱的高

    public Cylinder(){
        length = 1;
    }


    public double getLength(){
        return length;
    }
    public void setLength(double length){
        this.length = length;
    }
    //重写父类Circle 的方法，求圆柱的表面积
    public double findArea(){
//        return 3.14 * this.getRadius() * this.getRadius() * 2 + 2 * 3.14 * this.getRadius() * this.getLength();
        return super.findArea() * 2 + 2 * 3.14 * this.getRadius() * this.length;
    }
    //圆柱的体积
    public double findVolume(){
//        return Math.PI * this.getRadius() * this.getRadius() * length;
        return super.findArea() * length;
    }
}

package eightdemo;

/**
 * 在TestCylinder类中创建Cylinder类的对象，设置圆柱的底面半径和高，并输出圆柱的体积。
 */
public class TestCylinder {
    public static void main(String[] args) {
        Cylinder c = new Cylinder();

        double area = c.findVolume();
        System.out.println(area);

        c.setRadius(2.3);
        c.setLength(1.2);
        area = c.findVolume();
        System.out.println(area);

        c.findArea();
    }
}