练习19

#include <iostream>
using namespace std;


class Circle {
public:
Circle(float radius) {
this->radius = radius;
}
~Circle() {
}
float getArea() {
return 3.14 * radius * radius;
}
private:
float radius;
};


int main() {
float radius;
cout << "请输入圆的半径：";
cin >> radius;
Circle p(radius);
cout << "半径为" << radius << "的圆的面积为：" << p.getArea() << endl;
return 0;
}