* 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; } 
