circles.java

通过Java的定义主类跟子类来画圆

//父类的定义
class fatherCircle
{  //数据成员
   int x,y;
   double r;
   //构造方法
   fatherCircle(int a,int b)
   {
	setPoint(a,b);
	//半径缺省值1
	this.r=1;	
   }
   // 设置圆心
   public void setPoint(int a,int b)
   {
	x=a;
	y=b;
   }
   //得到X坐标
   public int getX()
   {
 	return x;
   }
   //得到X坐标
   public int getY()
   {
	return y;
   }
   public void show()
   {
	System.out.println("圆心坐标: "+"("+getX()+","+getY()+")");
   }
}

//子类的定义
class sonCircle extends fatherCircle
{
	double son_r;
	sonCircle(double r,int a,int b)
	{
		super(a,b);
		setR(r);
	}
	public void setR(double r)
	{
		son_r=r;
	}
	public double getson_r()
	{
		return son_r;
	}	
	 public void son_show()
  	 {	
		System.out.println("圆半径: "+getson_r());
		super.getX();
		super.getY();
		super.show();
		
   	}	
}



//主类
public class circles
{
	public static void main(String args[])
	{
		fatherCircle fatherObject = new fatherCircle(3,4);
		fatherObject.setPoint(3,4);
		fatherObject.show();
		sonCircle sonObject = new sonCircle(2.0,2,5);
		sonObject.setPoint(2,5);
		sonObject.setR(2.0);
		sonObject.son_show();
	
	}
}