c12_2.cpp

这我们老师对是面向对象程序设计（清华大学出版社）一书制作的PPT

#include<iostream.h>
class CContainer
{ 
protected:
	float r;
public:
	CContainer(float r1)
	{
		r=r1;
	}
	virtual float volume()=0;				//纯虚函数
	virtual float sarea()=0;
};
class Cylinder:public CContainer			
{
protected:
	float h;
public:
	Cylinder(float r1,float h1):CContainer(r1)
	{
		h=h1;
	}
	float volume()
	{
		return 3.1416*r*r*h;
	}
	float sarea()
	{ 
		return 2*3.1416*r*(h+r);
	}
};
class Global:public CContainer				
{

public:
	Global(float r1):CContainer(r1)
	{}
	float volume()
	{
		return 4.0/3*3.1416*r*r*r;
	}
	float sarea()
	{ 
		return 4*3.1416*r*r;
	}
};

class Square:public CContainer				
{
public:
	Square (float a):CContainer(a){}
	float volume()
	{
		return r*r*r;
	}
   float sarea()
	{ 
		return 6*r*r;
	}
};

void main()
{
	CContainer *ct;					 	
	ct=new Cylinder (1.0,2.0);
	cout<<"圆柱：表面积 "<<ct->sarea()<<" 体积 "<<ct->volume()<<endl;
	ct=new Global (1.0);
	cout<<"球：表面积 "<<ct->sarea()<<" 体积 "<<ct->volume()<<endl;
	ct=new Square (1.0);
	cout<<"正方体：表面积 "<<ct->sarea()<<" 体积 "<<ct->volume()<<endl;	
}