定義平面中的一個Circle類，

1編寫一個無引數建構函式，

2編寫一個有參的建構函式

3在主函式中呼叫無參建構函式生成圓的例項c1,呼叫有參建構函式生成圓的例項c2，呼叫例項方法判斷c1和c2是否重疊

class Point {
	double x;
	double  y;
	Point(double xx,double yy){
		x=xx;
		y=yy;
	}
	public  double disance(Point p1) {
		double dis;
		dis=(double)Math.sqrt((x-p1.x)*(x-p1.x)+(y-p1.y)*(y-p1.y))	;	
		return dis;	
	}
} 

class Circle {
		int radius;//半徑
		int x;
		int y;//圓心座標
		public Circle(){
			radius=2;
			x=1;
			y=1;
		}
		public Circle(int radius,int x,int y) {
			this.radius=radius;
			this.x=x;
			this.y=y;
		}
}
public class TextCircle {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Circle c1 = new Circle();
		Point p1=new Point (c1.x,c1.y);
		System.out.println("c1圓心座標為("+c1.x+","+c1.y+")半徑為："+c1.radius);	
		Circle c2=new Circle(1,2,3);
		System.out.println("c2圓心座標為("+c2.x+","+c2.y+")半徑為："+c2.radius);	
		Point p2=new Point (c2.x,c2.y);
		double dis=p1.disance(p2);
		System.out.println("兩個圓心的距離："+dis);
		
		if(dis>(c1.radius+c2.radius)) 
			System.out.println("不重疊");
		
		else 
			System.out.println("重疊");
		
		}
	}
 

執行結果：