C++类继承与派生的应用示例-优快云博客

本文展示了一个C++程序中类继承和派生的使用，具体包括坐标点类、圆类和圆柱体类的实现，通过构造函数、友元函数和成员函数展示了如何创建和操作这些几何对象。

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/* (程序头部注释开始)
* 程序的版权和版本声明部分
* Copyright (c) 2012, 烟台大学计算机学院学生
* All rights reserved.
* 文件名称：继承和派生

* 作者：晁阳
* 完成日期： 2012 年 4 月 23 日
* 版本号： t1.0
* 对任务及求解方法的描述部分
* 输入描述：继承和派生

*代码实现：

#include<iostream>

#include<Cmath>

#include<iomanip> 

#define PI 3.1415926

using namespace std;

class Point //定义坐标点类
{
public:
	Point(){x = 0; y = 0;}
	Point(double x0, double y0) {x = x0; y = y0;}
	~Point(){}  
    double getx(){return x;}  
    double gety(){return y;}  
    friend ostream &operator << (ostream & input, Point & c); //重载输入运算符
protected:
	double x, y;   //点的横坐标和纵坐标
};  

ostream &operator << (ostream & output, Point & c)//重载输出运算符
{
	output << "Point:(" << c.x << ", " << c.y << ")";
	return output;
}


class Circle : public Point//声明派生类Point
{
public:
	Circle(){r = 0;}
	Circle(double x0, double y0, double r);     //构造函数   
    ~Circle(){};  
    double getr(){return r;}  
    friend ostream &operator << (ostream & out, Circle & c);  
	double perimeter0();
	double area0();
protected:
	double r;
};

Circle :: Circle(double x0, double y0, double r1) : Point(x0, y0), r(r1){}    //构造函数 

ostream &operator << (ostream & output, Circle & c)  
{  
    output << "以" << "(" << c.getx() << "," << c.gety() << ")" << "为圆心， "  << "以" << c.r << "为半径的圆";  
  
    return output;  
}  


double Circle :: perimeter0()
{
	return PI * 2 * r;
}

double Circle :: area0()
{
	return PI * r * r;
}

class Cylinder : public Circle
{
public:
	Cylinder(){height = 0;}  
	Cylinder(double x1,double y1, double r1, double h); 
    ~Cylinder(){}  
	double area1();
	double volume();
	friend ostream &operator << (ostream & output, Cylinder & c); 
protected:
	double height;
};

Cylinder :: Cylinder(double x1,double y1, double r1, double h) : Circle(x1, y1, r1), height(h){}

ostream &operator << (ostream & output, Cylinder & c)  
{  
    output << "以" << "(" << c.getx() << "," << c.gety() << ")" << "为圆心, 以" << c.r << "为半径, 以" << c.height << "为高的圆柱体";  
  
    return output;  
}  

double Cylinder :: area1()
{
	return (area0() * 2 + perimeter0() * height);
}

double Cylinder :: volume()
{
	return area0() * height;
}

int main()  
{  
    Cylinder cy(1, 2, 4, 5);  
  
    cout << cy << endl;  
  
    cout << setiosflags(ios::fixed) << setprecision(3);  
  
    cout << "表面积是：" << cy.area1() << endl;  
  
    cout << "体积是：" << cy.volume() << endl;  
  
    system("pause");  
  
    return 0;  
}

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