定义基类Point（点）和派生类Circle（圆），求圆的周长。Point类有两个私有的数据成员float x,y;Circle类新增一个私有的数据成员半径float r和一个公有的求周长的函数getCircumference();主函数已经给出，请编写Point和Circle类。

#include
#include
using namespace std;
//请编写你的代码
int main()
{
float x,y,r;
cin>>x>>y>>r;
Circle c(x,y,r);
cout<<fixed<<setprecision(2)<<c.getCircumference()<<endl;
return 0;
}

输入格式:
输入圆心和半径，x y r中间用空格分隔。

输出格式:
输出圆的周长，小数点后保留2位有效数字。

输入样例:
1 2 3

输出样例:
在这里给出相应的输出。例如：

Point constructor called
Circle constructor called
18.84
Circle destructor called
Point destructor called

#include<iostream>
#include<iomanip>
#define PI 3.14
using namespace std;
class Point {
protected:
    float X, Y;
public:
    Point() {}
    Point(float x, float y) :X(x), Y(y) {
        cout << "Point constructor called" << endl;
    }~Point() {
        cout << "Point destructor called" << endl;
    }
};
class Circle :public Point {
    float R;
public:
    float c;
    Circle() {}
    Circle(float x, float y, float r) :Point(x, y), R(r) {
        cout << "Circle constructor called" << endl;
    };
    ~Circle() {
        cout << "Circle destructor called" << endl;
    }
    float getCircumference();
};
float Circle::getCircumference() {
    c = PI * R * 2;
    return c;
}int main()
{
    float x, y, r;
    cin >> x >> y >> r;
    Circle c(x, y, r);
    cout << fixed << setprecision(2) << c.getCircumference() << endl;
    return 0;
}

2020/4/12----By Suki