Question

定义一个类,分别求圆和球体的面积?

Answer 1

class circle{ public circle(int r){ R=r; } private double R; public double getalllong(){ return 2*Math.PI*R; } public double getarea(){ return Math.PI*R*R; } } public static void main(String[] a){ circle r=new circle(2.5); System.out.println("周长："+r.getalllong()+"面积:"+r.getarea()); }