第十周 任务三 3-1 先声明点类，在派生出圆类 圆柱类

* 程序的版权和版本声明部分

* Copyright (c) 2011, 烟台大学计算机学院学生 

* All rights reserved.

* 文件名称：先声明点类，在派生出圆类 圆柱类

* 作    者：  张启立                           

* 完成日期：  2012年 4 月 16 日

* 版 本 号： 10-3-1   

#include <iostream>

#include<Cmath>   
  
#include<iomanip>   
  
using namespace std;

const double PI = 3.141592653;

class Point//点类声明
{
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);  
protected:  
    double x, y;   //点的横坐标和纵坐标   
};
ostream &operator << (ostream & input, Point & c)
{
	input << "点:(" << c.x << "," << c.y << ")";  
  
    return input;  
}
class Circle: public Point   //以点类为基类的派生类
{  
public:  
    Circle(){radius = 0;}  
    Circle(double x0, double y0, double r):Point(x0, y0),radius(r){ }      //构造函数   
    ~Circle(){} 
    double getr(){return radius;}  
	double area1();
    friend ostream &operator << (ostream & out, Circle & c);  
protected:  
    double radius;  
};  
double Circle::area1() //圆形面积
{
	double c_area = PI * getr() * getr();

	return c_area;
}
ostream &operator << (ostream & out, Circle & c)  
{  
    out << "(" << c.getx() << "," << c.gety() << ")" << "为圆心" << c.radius << "为半径的圆";  
  
    return out;  
}  
  
class Cylinder: public Circle  //以圆类为基类的派生类
{  
public:  
    Cylinder(){height = 0;}  
    Cylinder(double x1,double y1, double r1, double h):Circle(x1, y1, r1), height(h){ }  
    ~Cylinder(){}  
    double geth(){return height;}  
    double area2();  
    double volume();  
    friend ostream &operator << (ostream & out, Cylinder & c);  
private:  
    double height;  
};  
   
double Cylinder::area2()  
{  
  
    //double c_area = PI * getr() * getr();  
  
    double c_cir = 2 * PI * getr() * height;   //圆柱侧面积
  
    return (c_cir + 2 * area1());  
}  
  
double Cylinder::volume()  
{  
    return (PI * getr() * getr() * height);  
}  
  
ostream &operator << (ostream & out, Cylinder & c)  
{  
    out << "(" << c.getx() << "," << c.gety() << ")" << "为圆心" << c.radius << "为半径" << c.height << "为高的圆柱体";  
  
    return out;  
}  
  
int main()  
{  
    Cylinder cy(2, 2, 1, 3);  
  
    cout << cy << endl;  
  
    cout << setiosflags(ios::fixed) << setprecision(2);  
  
    cout << "表面积是：" << cy.area2() << endl;  
  
    cout << "体积是：" << cy.volume() << endl;  
  
    system("pause");  
  
    return 0;  
}