circle.java

java2应用开发指南第一版

//Circle.java
import java.awt.Point;
import java.math.*;
class Circle
{
	//定义的成员变量
	public int nOrignX;
	public int nOrignY;
   public float fRadius;
   //构造函数
	public Circle(int nOrignX,int nOrignY,float fRadius)
	{
			//完成成员变量的初始化
			this. nOrignX = nOrignX;
			this. nOrignY = nOrignY;
			this.fRadius = fRadius;
	}
	//取得原点坐标的方法
	public Point getOrign()
	{
		//申请Point类的实例
		Point pntPoint = new Point();
	   //Point类实例的成员赋值
		pntPoint.x = nOrignX;
		pntPoint.y = nOrignY;
	   //返回Point的实例pntPoint
		return pntPoint;
	}
	//获取圆半径的方法
	public float getRadius()
	{
		//返回圆的半径
		return fRadius;
	}
	//计算圆面积的方法
	public float getArea()
	{
		return (float)Math.PI*fRadius*fRadius;
	}
	public static void main(String args[])
	{
	   //创建对象实例
		Circle aCircle = new Circle(0,0,10);
	    //调用getRadius方法
		float fRadius = aCircle.getRadius();
	    //调用getArea方法
	    float fArea = aCircle.getArea();
	    System.out.println("当前圆的半径为"+fRadius);
	    System.out.println("圆的面积为"+fArea);
	}
}