To reach - the ninth work

I, entitled: class rectangle having a long, wide, and the method of calculating the area of ​​three areas of the member variables, and then create a subclass of the class of rectangular - square class, method of calculating the overwritten area. In the cartridge type, the class object to create a rectangular bottom made variable as a cylinder member, define methods soled and volume calculation. In the main class, computing a rectangular bottom cylinder volume object, and then use a method to replace soled square bottom, and to calculate the volume again.

Second, the code and comments

/ ** 
 * define a rectangle class. There are long. width. Three members of the variable area, a rectangular writing class constructor. The method has two parameters, a method of calculating the area definition 
 * define a rectangular square class inherits class constructor is defined. Which method a parameter. Call the parent class constructor with a super () constructor years. Rewritable area calculated 
 * method. A cylinder defined class. There rectangle p1. high. Volume three member variables. The method defined soled method of obtaining the volume of the cylinder. 
 * / 
Class Juxing {
     int Chang;
     int Kuan;
     int Area; 

    public Juxing ( int Chang, int Kuan) {
         the this .chang = Chang;
         the this .kuan = Kuan; 
    } 

    void setArea () { 
        Area = * Chang Kuan; 
    } 

} 

classzhengfangxing the extends Juxing { 

    public zhengfangxing ( int Bian) {
         Super (Bian, Bian); 
    } 

    void setArea () { 
        Area = Chang * Chang; 
    } 
} 

class zhuti { 
    Juxing P1; 
    int Gao;
     int Volum; 

    zhuti (Juxing P1, int Gao) {
         the this .P1 = P1;
         the this .gao = Gao; 
    } 

    void SETP1 (Juxing P1) { // soled method of 
        the this .P1 =P1; 
    } 

    void getvolum () { 
        Volum = p1.area * Gao; 
    } 
} 

public  class examplesuper {
     public  static  void main (String [] args) { 
        Juxing P1 = new new Juxing (. 3,. 4 ); 
        p1.setArea (); 
        C zhuti = new new zhuti (P1,. 5 ); 
        c.getvolum (); 
        System.out.println ( "rectangular cylinder volume:" + c.volum); 
        c.setp1 ( new new zhengfangxing (. 5 )); 
        C. p1.setArea ();
        c.getvolum (); 
        System.out.println ( "square cylinder volume" + c.volum); 

    } 

}

 

operation result: