point3d.java

java程序设计 清华出版社 孙燮华老师编写的程序源代码

//Point3D.java
class POINT{
  int x, y;
  
  POINT(int x1, int y1){
    x =x1;
    y =y1;
  }
  
  POINT(){
    this(0, 0);
  }
  
  void moveTo (int x1, int y1){
    x = x1;
    y = y1;
  }
}

class Point3D extends POINT{
  int z;                              //新的成员变量
  
  public Point3D(int x, int y, int z){//新的成员方法
    super(x, y);                      //super代表当前类的直接父类POINT
    this.z = z;
  }
  
  public Point3D(){                   //新的成员方法
    this(0, 0, 0);                    //this代表当前类Point3D
  }
  
  public static void main(String[] args){
  	Point3D p3=new Point3D(1,2,3);
  	System.out.println("p3.x = "+ p3.x);
  	System.out.println("p3.y = "+ p3.y);
  	System.out.println("p3.z = "+ p3.z);
  	  	
  	Point3D p03=new Point3D();
  	System.out.println("p03.x = "+ p03.x);
  	System.out.println("p03.y = "+ p03.y);
  	System.out.println("p03.z = "+ p03.z);
  	
  	p03.moveTo(88,99);
  	System.out.println("\nAfter using p03.moveTo(88,99)");
  	System.out.println("p03.x = "+ p03.x);
  	System.out.println("p03.y = "+ p03.y);
  	System.out.println("p03.z = "+ p03.z);
  }  
}