2012年 上半年 第十三周 C++程序设计 （四十）

【任务】设计一个抽象类CSolid，含有两个求表面积及体积的纯虚函数。设计个派生类CCube、CBall、CCylinder，分别表示正方体、球体及圆柱体。在main()函数中，定义基类的指针p(CSolid *p;)，利用p指针，输出正方体、球体及圆柱体对象的表面积及体积。

#include <iostream>using namespace std;class CSolid{public:virtual double area() const = 0;virtual double volume() const = 0;};class CCube:public CSolid{public:CCube(float lengh, float wide, float high);virtual double area() const {return lengh * wide + lengh * high + wide * high;}virtual double volume() const {return lengh * wide * high;}private:double lengh;double wide;double high;};CCube::CCube(float lengh, float wide, float high){this->lengh = lengh;this->wide = wide;this->high = high;}class CBall:public CSolid{public:CBall(double R) {this->R = R;}virtual double area() const {return 4 * 3.14 * R * R;}virtual double volume() const {return (double)3 / 4 * 3.14 * R * R * R;}private:double R;};class CCylinder:public CSolid{public:CCylinder(double R, double high) {this->R = R; this->high = high;}virtual double area() const {return 3.14 * R * R + 2 * 3.14 * R * high;}virtual double volume() const {return 3.14 * R * R * high;}private:double R;double high;};int main(){CCube cube(3, 4, 5);CSolid *cs = &cube;cout << "正方体的表面积为: " << cs->area() << endl;cout << "正方体的体积为: " << cs->volume() << endl;CBall ball(2);cs = &ball;cout << "球体的表面积为: " << cs->area() << endl;cout << "球体的体积为: " << cs->volume() << endl;CCylinder cylinder(2, 4);cs = &cylinder;cout << "圆柱体的表面积为: " << cs->area() << endl;cout << "圆柱体的体积为: " << cs->volume() << endl;system("pause");return 0;}

正方体的表面积为: 47正方体的体积为: 60球体的表面积为: 50.24球体的体积为: 18.84圆柱体的表面积为: 62.8圆柱体的体积为: 50.24请按任意键继续. . .