22 面向对象三大特征的案例

案例:创建一个图形类(shape)：长和宽 ,求面积和周长的方法

矩形类(Rectangle)、正方形类(Square)、圆形类(circle)

public class Dome {

    public static void main(String[] args) {
        Shape s=new Rectangle(4, 5);
        System.out.println(s.Get_MianJi());
        Shape s1=new circle(2);
        System.out.println(s1.Get_ZhouChang());
    }

}

class Shape{
    private int chang,kuan;

    public int getChang() {
        return chang;
    }

    public void setChang(int chang) {
        this.chang = chang;
    }

    public int getKuan() {
        return kuan;
    }

    public void setKuan(int kuan) {
        this.kuan = kuan;
    }

    public double Get_ZhouChang()
    {
        return 0.0;
    }
    public double Get_MianJi()
    {
        return 0.0;
    }
    public Shape(int chang,int kuan) {
        this.chang=chang;
        this.kuan=kuan;
        
    }
}
//矩形类
class Rectangle extends Shape{
    public Rectangle(int chang, int kuan) {
        super(chang, kuan);
    }
    @Override
    public double Get_ZhouChang() {

        return 2*(this.getChang()+this.getKuan());
    }
@Override
public double Get_MianJi() {
    return this.getChang()*this.getKuan();
}
}
//正方形 类
class Square extends Rectangle{  //正方形类继承长方形类

    public Square(int chang) {
        super(chang, chang);  
    }

}
//圆形类
class circle extends Shape{

    public circle(int chang) {
        super(chang, chang);
    }
    @Override
    public double Get_ZhouChang() {
        return 2*this.getChang()*3.14;
    }
    @Override
    public double Get_MianJi() {
        return this.getChang()*this.getChang()*3.14;
    }
}