point3d.java

这个程序提供了JAVA很基础的CLASS的应用举例

import java.awt.Graphics;
import java.applet.Applet;
import java.util.*;

class Point{
    double x,y;
  
    Point(double x,double y){
    	this.x=x;
    	this.y=y;
    	}
    double getX(){return x;}
    double getY(){return y;}
    double distance(Point P1)
    {
        double m;
        double n;
    	m=(x-P1.x)*(x-P1.x);
    	n=(y-P1.y)*(y-P1.y);
       return Math.sqrt(m+n);
    }
    void print(){
       System.out.println(": x="+x+" y="+y);}
}
    
class Point3D extends Point{
    double z;
  
    Point3D(double x,double y,double z){
    	super(x,y);
    	this.z=z;  }

    double getZ(){return z;}
    double distance(Point3D P1){
    Point p=new Point(x,y);
    Point p1=new Point(P1.x,P1.y);
    p.distance(p1);
    Point p2=new Point(0,z);
    Point p3=new Point(p.distance(p1),P1.z);
    return p2.distance(p3);
   
     }
    void print(){
       System.out.println(": x="+x+" y="+y);
                }
}
    class object{
     public static void main(String args[]){
       
       double d;
      
       Point3D p=new Point3D (0,0,0);
       Point3D p1=new Point3D(3,4,12);
      
       System.out.println("横坐标是"+p1.getX());
       System.out.println("纵坐标是"+p1.getY());
       System.out.println("竖坐标是"+p1.getZ());
       //System.out.println("please input y!");
           
       //P.getY();
       d=p.distance(p1);
       System.out.println("distance is "+d);
       
       
       
        
       
                                            }

                 }