circle.java

（1） 编写一个代表圆柱体的Cylinder类

 package p3;
import p2.Point;
public class circle
{
public	Point center;
public	int r;
public  circle(){};
public	circle(int x,int y,int r)
	{
		center=new Point(x,y);
		this.r=r;
	}
public	circle(Point p,int r)
	{
		center=p;
		this.r=r;
	}
public Point getPoint()
{
	return center;
}
public int getX()
{
  return center.getx();
}
public int getY()
{
  return center.gety();
}
public int getR()
{
	return r;
}
 public	double length()
	{
		return 2*Math.PI*r;
	}
 public	double area()
	{
		return Math.PI*r*r;
	}
 public	int relation(circle c)
	{
		double dis;int radiu,tance;
		dis=center.distance(c.center);
		radiu=r+c.r;
		tance=Math.abs(r-c.r);
		if(radiu<dis)
		  return 3;//xiang li;		 
		if(radiu<=dis&&dis>tance)
		   return 2;//jiao;
		if(center.getx()==c.center.getx()&&center.gety()==c.center.gety())
		   if(r==c.r)return 0;
		     else return 1;
		 return 4;
	}
	public boolean equals(circle c)
	{
		return center.equals(c.getPoint())&&(r==c.getR());
	}
	public String toString()
	{
		return "The center is "+center.toString()+",the radiu is "+r;
	}
}