C++创建类并调用类里的函数

#include
#include 
#include
using namespace std;//使用标准命名空间，不然下面都要写std::cout<<..
class Cy{
	double radius,height;
	public:
		double volume(){
			return M_PI*radius*height;
		}
		double area(){
			return M_PI*radius*radius;
		}
		Cy(double i,double h):radius(i),height(h){
		};
};
	int main(){
		double r,h;
		cout << "请输入半径:";
		cin >> r;
		cout << "请输入高:";
		cin >> h;
		Cy X(r,h);
		double v = X.volume();
		double a = X.area();
		cout << "体积是:" << fixed << setprecision(10) << v << endl << "面积是:"<<  a << endl;//定义输出精度为10位小数
		return 0;
	}