【说明】 以下程序的功能是计算正方体、球体和圆柱体的表面积和体积并输出。 程序由4个类组成：类cube、sphere和cylinder分别表示正方体、球体和圆柱体；抽象类 container为抽象类，提供了两个纯虚拟函数surface_area()和volum()，作为通用接口。 【C++程序】 #include＜iostream.h＞ #define pi 3.1416 class container｛ protected: double radius; public: container(double radius) container::radius=radius; virtual double surface_area()=0; virtual double velum()=0; ; class cube: (1) //定义正方体类 public: cube(double radius):container(radius); double surface_area () return 6 * radius * radius; double volum() return radius * radius * radius; ; class sphere: (2) //定义球体类 public: sphere(double radius): container(radius); double surface_area() return (3) ; double volum() return pi * radius * radius * radius * 4/3; ; class cylinder: (4) //定义圆柱体类 double height; public: cylinder(double radius,double height):container(radius) container::height=height; double surface_are a () return 2 * pi * radius * (height+radius); double volum () return (5) ; ; void main() container * p; cube obj1 (5); sphere obj2(5); cylinder obj3(5,5); p=&obj1; cout＜＜“正方体表面积”(＜＜p-＞surface_area()＜＜end1; cont＜＜“正方体体积”＜＜p-＞volume()＜＜end1; p=&obj2; cout＜＜“球体表面积”＜＜p-＞surface_area()＜＜end1; cout＜＜“球体体积”＜＜p-＞volume()＜＜end1; p=&obj3; cout＜＜“球体表面积”＜＜p-＞surface_area()＜＜end1; cout＜＜“球体体积”＜＜p-＞volume()＜＜end1;