用Java程序编写

题目

用Java程序编写
定义一个Circle类,该类拥有一个存储圆半径的属性（Radius）,并撰写设置、取得圆半径、计算圆周、计算圆面积的四个方法；然后定义一个存储5个Circle对象的数组,这5个Circle对象的半径分别为1、2、3、4、5,并计算这5个Circle对象的面积总和.

答案

public class Circle{
private double radius;

public Circle(double r){
this.radius = r;
}

public static void main(String args[]){
Circle[] ary = new Circle[5];

ary[0] = new Circle(1);
ary[1] = new Circle(2);
ary[2] = new Circle(3);
ary[3] = new Circle(4);
ary[4] = new Circle(5);

double area = 0;

for(int i = 0;i < ary.length; i++){
area = area + ary[i].area();
}

System.out.println("Total area is: " + area);
}
public double getRadius() {
return radius;
}
public void setRadius(double radius) {
this.radius = radius;
}

public double area(){
return Math.PI * radius * radius;
}

public double circle(){
return 2 * Math.PI * radius;
}
}
-------------
Total area is: 172.7875959474386