點類，圓類，圓柱類

/* Copyright (c) 2012, 煙台大學電腦學院       * All rights reserved.       * 檔案名稱:text.cpp       * 作    者：  胡穎      *完成日期：2013年5月20日       * 版 本 號：v1.0       *       * 輸入描述：無   * 問題描述：（1）先建立一個Point(點)類，包含資料成員x,y(座標點)；（2）以Point為基類，派生出一個Circle(圓)類，增加資料成員 (半徑)；（3）再以Circle類為直接基類，派生出一個Cylinder(圓柱體)類，再增加資料成員h(高)。要求編寫程式，設計出各類中基本的成員函數（包括建構函式、解構函式、修改資料成員和擷取資料成員的公用介面、用於輸出的重載運算子“<<”函數等），使之能用於處理以上類對象，最後求出圓格柱體的表面積、體積並輸出。      * 程式輸出：輸出點，圓的資訊和圓柱的資訊 * 問題分析：無   * 演算法設計：略       */             #include <iostream>using namespace std;class Point{public:      Point(double x=0,double y=0);//初始化點座標為（0,0）      double getX()const      {          return x;      }      double getY()const      {          return y;      }      void setPoint(double,double);      friend ostream & operator<<(ostream &,const Point &);protected:      double x,y;};Point::Point(double a,double b){   x=a;   y=b;}void Point::setPoint(double a,double b){    x=a;    y=b;}ostream & operator<<(ostream &output,const Point &p){    output<<"point:["<<p.x<<","<<p.y<<"]"<<endl;    return output;}class Circle:public Point{public:    Circle(double x=0,double y=0,double r=0);    void setRadius(double);    double getRadius()const ;    double area()const;    friend ostream & operator<<(ostream &,const Circle &);protected:    double radius;};Circle::Circle(double a,double b,double r):Point(a,b),radius(r){}void Circle::setRadius(double r){    radius=r;}double Circle::getRadius()const{    return radius;}double Circle::area()const{    return 3.14159*radius*radius;}ostream & operator<<(ostream &output,const Circle &c){   output<<"center=["<<c.x<<","<<c.y<<"],r="<<c.getRadius()<<",area="<<c.area()<<endl;   return output;}class Cylinder:public Circle{public:    Cylinder(double x=0,double y=0,double r=0,double h=0);    void setHeight(double);    double getHeight()const;    double area()const;    double volume()const;    friend ostream & operator<<(ostream &,const Cylinder &);protected:    double height;};Cylinder::Cylinder(double a,double b,double r,double h):Circle(a,b,r),height(h){}void Cylinder::setHeight(double h){    height=h;}double Cylinder::getHeight()const{    return height;}double Cylinder::area()const{    return 2*Circle::area()+2*3.14159*radius*height;//求面積借用Circle的成員函數area的方式為Circle::area()}double Cylinder::volume()const{   return Circle::area()*height;}ostream & operator<<(ostream &output,const Cylinder &cy){    output<<"center=["<<cy.x<<","<<cy.y<<"],r="<<cy.radius<<",h="<<cy.height<<",area="<<cy.area()<<",volume="<<cy.volume()<<endl;    return output;}int main(){  Point p(3.5,6.4);  cout<<"x="<<p.getX( )<<",y="<<p.getY( )<<endl;  p.setPoint(8.5,6.8);  cout<<"p:"<<p<<endl;  Circle c(1.2,2.2,3.2);  cout<<"original circle:x="<<c.getX()<<",y="<<c.getY()<<",r="<<c.getRadius()<<",area="<<c.area()<<endl;  c.setPoint(5,5);  cout<<"new circle:"<<c;  Cylinder cy1(1.2,2.2,3.2,4.2);  cout<<"original Cylinder:x="<<cy1.getX()<<",y="<<cy1.getY()<<",r="<<cy1.getRadius()<<",h="<<cy1.getHeight()<<",area="<<cy1.area()<<",volume="<<cy1.volume()<<endl;  cy1.setPoint(5,5);  cy1.setRadius(2.1);  cy1.setHeight(3);  cout<<"new Cylinder:"<<cy1;  return 0;}

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