testcomparable.java

本书是一本为Java学习者在基础内容学习结束后进行课程设计时提供参考的指导书

package apibook.c2.s3;

import java.util.*;
import java.awt.*;
public class TestComparable {

  public TestComparable() {
  }
  public static void main(String[] args) {
    TreeSet set = new TreeSet();
    Random r= new Random();
    for (int i = 0; i < 10; i++) {
      set.add(new MyPoint(r.nextInt(2002),r.nextInt(2003)));
    }
    for(Iterator it=set.iterator();it.hasNext();){
      MyPoint p=(MyPoint)it.next();
      System.out.println(p.x+" "+p.y);
    }
  }
}
class MyPoint extends Point implements Comparable{
      MyPoint(int x,int y){
        super(x,y);
      }
      public int compareTo(Object o){
        Point p= (Point)o;
        double d1=Math.sqrt(x*x+y*y);
        double d2=Math.sqrt(p.x*p.x+p.y*p.y);
        if (d1<d2) {
          return -1;
        }
        else if(d1>d2){
          return 1;
        }
        else{
          return 0;
        }
      }
}