（3）编写一个测试类PointDemo，在该类中创建两个Point类的实例对象，即坐标点（3,3）和（4,5），并计算这两个点间的距离。

public class Point
{
public int x;
public int y;
public Point(int x,int y)
{
this.x=x;
this.y=y;
}
public Point(int x)
{
this(x,x);
}
public double distance()
{
return this.distance(0,0);
}
public double distance(int x,int y)
{
return Math.sqrt((this.x-x)(this.x-x)+(this.y-y)(this.y-y));
}
public double distance(Point p)
{
return this.distance(p.x,p.y);
}
}

Point类：

public class Point {
    private double xx;
    private double yy;
    
    public Point(){xx = 0;yy=0;}
    public Point(double x,double y){xx =x;yy = y;}
    public double getXx() {
        return xx;
    }
    public void setXx(double xx) {
        this.xx = xx;
    }
    public double getYy() {
        return yy;
    }
    public void setYy(double yy) {
        this.yy = yy;
    }
    
}

PointDemo类：

public class PointDemo {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Point p1 = new Point(3,3);
        Point p2 = new Point(4,5);
        double dis = Math.sqrt((p1.getXx() - p2.getXx())*(p1.getXx() - p2.getXx()) + (p1.getYy()-p2.getYy())*(p1.getYy()-p2.getYy()));
        System.out.println("两点间的距离=" + dis);
    }

}