圆的程序怎么编程？

C++编程

#includeusingnamespacestd；#definePI3.141592635classCircle{public:Circle():_r(0.f){}Circle(doubler):_r(r){}Circle(constCircle&circle){this->_r=circle._r；}voidsetRadius(doubler){this->_r=r；}doubleArea(){returnPI*this->_r*this->_r；}doubleCircumference(){return2*PI*this->_r；}private:double_r；}；intmain(){Circlec1；doublex；cin>>x；c1.setRadius(x)；cout<<"c1面积："旅指<<c1.Area()<<endl；cout<<"c1周长："<<c1.Circumference()<<endl；Circlec2(2*x)；cout<<"c2面前镇源积："<<c2.Area()<<endl；cout<<"c2周长："<<c2.Circumference()<<endl；Circlec3(c1)；cout<<"c3面积："<<c3.Area()<<endl；cout<<"慧态c3周长："<<c3.Circumference()<<endl；return0；}

#include <iostream>

using namespace std

   

#define PI 3.141592635

  

class Circle

{

public:

    Circle() : _r(0.f){}

    Circle(double r) : _r(r){}

    Circle(const Circle& circle)

    {

        this->_r = circle._r

    }

    void setRadius(double r)

    {

        this->_r = r 

    }  

    double Area()

    {

        return PI * this->_r * this->_r 

    }   

    double Circumference()

    {    

       冲桥 老雹return 2 * PI * this->_r 

    }     

   

private:

    double _r      

}  

int main()

{

    Circle c1

    double x

    cin >> x

    c1.setRadius(x)

    cout << "c1面积：" 侍判帆<< c1.Area() << endl

    cout << "c1周长：" << c1.Circumference() << endl

    Circle c2(2 * x) 

    cout << "c2面积：" << c2.Area() << endl

    cout << "c2周长：" << c2.Circumference() << endl 

    Circle c3(c1)  

    cout << "c3面积：" << c3.Area() << endl

    cout << "c3周长：" << c3.Circumference() << endl  

       

    return 0 

}

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