import java.util.Scanner;
public class Main {
    public static void main(String[] args){
        double pai = 3.14,Round,ans = 0;;
        Scanner s = new Scanner(System.in);
        int h , r;
        int elephant = 20000;
        h = s.nextInt();
        r = s.nextInt();
        Round = var(h,r,elephant,pai,0,0);
        System.out.println(Round);
    }
    static double var(int h,int r,double e,double pai,double ans,int ansxs){
        if(ans >= e){
            return ansxs;
        }else {
            ans += r * r * pai * h;
            if (ans < e) {
                var(h, r, e, pai, ans, ansxs + 1);
            }
        }
        //错误，要有return语句！
    }
}

我以前是学c++的，为什么c++和java不一样？