求圆的周长和面积的多文件实现

一个类对应一个头文件和一个.cpp文件，在头文件写类的声明，在.cpp文件中写类的实现。

1 //Circle.h 2 #pragma once 3  4 class Circle 5 { 6 public: 7     //设置半径 8     void set(double r); 9     //得到半径10     double get();11     //得到周长 12     double getCircleGirth();13     //得到面积14     double getCircleArea();15 private:16     double m_r;17     double m_area;18     double m_girth;19 20 };

 

1 //Circle.cpp 2  3 #include "Circle.h" 4  5 void Circle::set(double r) 6 { 7     m_r = r; 8 } 9 10 //得到半径11 double Circle::get()12 {13     return m_r;14 }15 //得到周长 16 double Circle::getCircleGirth()17 {18     m_girth = 2 * 3.14*m_r;19     return m_girth;20 }21 //得到面积22 double Circle::getCircleArea()23 {24     m_area = 3.14*m_r*m_r;25     return m_area;26 }

 

//主文件#define _CRT_SECURE_NO_WARNINGS#include 
     
      #include "Circle.h"using namespace std;int main(void){    Circle c;    c.set(10);    cout << "圆的半径：" << c.get() << endl;    cout << "圆的周长：" << c.getCircleGirth() << endl;    cout << "圆的面积：" << c.getCircleArea() << endl;}