Question

设计程序计算圆的面积（要求：定义一个circle类，包含数据成员int radius）

Answer 1

#include<iostream.h>
const float PI=(float)3.14159;
class Circle
{
public:
Circle(float r);
float Area();
private:
float radius;
};
Circle::Circle(float r){radius=r;}
float Circle::Area()
{
return PI*radius*radius;
}
void main()
{
float radius;
float FenceCost;
cout<<"请输入半径"<<endl;
cin>>radius;
Circle pool(radius);
FenceCost=pool.Area();
cout<<"圆的面积为："<<FenceCost<<endl;
}
打得好辛苦，多加点分吧