定义圆类circle,数据成员有半径radius,成员函数有默认构造函数,默认半径为10,构造函数,计算圆面积圆周长以及

#include#define PI 3.14159class Circle{private:float radius,girth,area;public:Circle(float r=0);//构造函数（以半径为参数,缺省值为0）Circle(Circle &c);//复制构造函数void input();//输入半径void jisuan();//计算周长、面积void output();//输出半径、周长和面积};Circle::Circle(float r){radius=r;}Circle::Circle(Circle &c){radius=c.radius;}void Circle::input(){coutradius;}void Circle::jisuan(){ girth=2*PI*radius; area=PI*radius*radius;}void Circle::output(){cout