Question

C++ 设计一个圆类，计算圆的面积和周长。

请各位大大帮帮忙，用C++程序 设计一个圆类，计算圆的面积和周长。
谢谢了

Answer 1

#include<iostream>
using namespace std;

class Circle
{
double radius; //圆的半径
int x,y; //圆心坐标
static const double PI;
public:
Circle(double radius,int x=0,int y=0);
double getArea();
double getCircleLength();
};

const double Circle::PI=3.1415;

Circle::Circle(double radius, int x , int y )
{
this->radius=radius;
this->x=x;
this->y=y;
}

double Circle::getArea()
{
return PI*radius*radius;
}

double Circle::getCircleLength()
{
return 2*PI*radius;
}

int main()
{
Circle c(3.2);
cout<<"圆的面积为: "<<c.getArea()<<endl;
cout<<"圆的周长为: "<<c.getCircleLength()<<endl;
return 0;
}

Answer 2

#include <iostream.h>
#define PI 3.1415926
class Circle{
private:
double point_x,point_y;//圆心
double radius;//半径
public:
Circle(double initial_x = 0.0,double initial_y = 0.0,double initial_r = 1.0){
point_x = initial_x;
point_y = initial_y;
radius = initial_r;
}
~Circle(){
}
double GetArea(){
return(PI*radius*radius);
}
double GetPerimeter(){
return(2*PI*radius);
}
};
void main(){
Circle myCircle = Circle(0,0,10);
cout<<"面积="<<myCircle.GetArea()<<endl;
cout<<"周长="<<myCircle.GetPerimeter()<<endl;
}