//ComputeArea 為類名
public class ComputeArea {
	//Main 方法 
public static void main(String args[]){
	//定義變量radius、area和常量PI
	double radius;
	double area;
	final double PI= 3.1415926;
	//給變量賦值Radius
	radius = 20;
	//Compute area
	area = radius * radius * PI;
	//輸出結果
	System.out.println("The area for the circle of  radius " +radius + " is " + area);
}
}