Question

C++一个圆类，要求定义构造函数（以半径为参数，缺省值为0，周长和面积在构造函数中生成）和复制构造函数

属性为半径（radius）、圆周长和面积，操作为输入半径并计算周长、面积，输出半径、周长和面积。如何正确输出？

#include<iostream>
using namespace std;

const double PI=3.141593;

class Circle{
public:
Circle(float r);
float circumference();
float area();
private:
float radius;
};

Circle::Circle(float r){
radius=r;
}

float Circle::circumference(){
return 2*PI*radius;
}

float Circle::area(){
return PI*radius*radius;
}

int main(){
float radius;
cout<<"Enter the radius:";
cin>>radius;
Circle circle(radius);

float circumference=Circle.circumference;
cout<<"Circumference is "<<circumference<<endl;

float area=Circle.area;
cout<<"Area is "<<area<<endl;

return 0;
}

Answer 1

改成
float circumference=Circle.circumference();
cout<<"Circumference is "<<circumference<<endl;

float area=Circle.area();
cout<<"Area is "<<area<<endl;

return 0;
}
再试试……