c++圆类程序填空求大佬帮忙

Question

#include
using namespace std;
//定义圆类

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int main() {
___________________; //声明圆类对象r，默认构造(圆的半径=1)
cout<<"Radius:"<<r.getRadius();
cout<<",Area:"<<___________________;
cout<<",Perimeter:"<<r.getPerimeter()<<endl;
cout<<endl;

___________________; //改变圆的半径为6
cout<<"Radius:"<<___________________;
cout<<",Area:"<<r.getArea();
cout<<",Perimeter:"<<r.getPerimeter()<<endl;
cout<<endl;
___________________; //声明另一个圆类对象r1(半径初值为8)
cout<<"Radius:"<<r1.getRadius();
cout<<",Area:"<<r1.getArea();
cout<<",Perimeter:"<<___________________<<endl;
cout<<endl;
return 0;
}
输入
无
输出
圆的半径、面积和周长
输入样例 1
无
输出样例 1
Radius:1,Area:3.14159,Perimeter:6.28319

Radius:6,Area:113.097,Perimeter:37.6991

Radius:8,Area:201.062,Perimeter:50.2655

Answer 1

#include <iostream>

using namespace std;
//定义圆类
class Circle
{
public:
    float r;
public:
    Circle() : r(1) {}
    Circle(float _r) : r(_r) {}
    void setRadius(float r) { this->r = r; }
    float getRadius() { return r; }
    float getArea() { return 3.14 * r * r; }
    float getPerimeter() { return 3.14 * r * 2; }
};

int main() {
    Circle r; //声明圆类对象r，默认构造(圆的半径=1)
    cout<<"Radius:"<<r.getRadius();
    cout<<",Area:"<<r.getArea();
    cout<<",Perimeter:"<<r.getPerimeter()<<endl;
    cout<<endl;
    r.setRadius(6); //改变圆的半径为6
    cout<<"Radius:"<<r.getRadius();
    cout<<",Area:"<<r.getArea();
    cout<<",Perimeter:"<<r.getPerimeter()<<endl;
    cout<<endl;
    Circle r1(8); //声明另一个圆类对象r1(半径初值为8)
    cout<<"Radius:"<<r1.getRadius();
    cout<<",Area:"<<r1.getArea();
    cout<<",Perimeter:"<<r.getPerimeter()<<endl;
    cout<<endl;
    return 0;
}