??项目三-立体类族共有的抽象类

项目3-立体类族共有的抽象类

设计一个抽象类CSolid，含有用于求表面积及体积的两个纯虚函数。设计派生类CCube、CBall、CCylinder，分别表示正方体、球体及圆柱体。在main()函数中，定义CSolid *p;（p是指向基类的指针，且这个基类是个抽象类）。要求利用这个p指针，能够求出正方体、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 SurfaceArea() const=0;
	virtual double Volume() const=0;
};
class CCube : public CSolid
{
public:
	CCube(double len=0);
	double SurfaceArea() const;
	double Volume() const;
private:
	double length;

};
CCube::CCube(double len)
{
	length=len;
}
double CCube::SurfaceArea() const
{
	double c;
	c=6*length*length;
	return c;
}
double CCube::Volume() const
{
	double c;
	c=length*length*length;
	return c;
}
class CBall : public CSolid
{
private:
	double radius;
public:
	CBall(double r=0);
	double SurfaceArea() const;
	double Volume() const;
};
CBall::CBall(double r)
{
	radius=r;
}
double CBall::SurfaceArea() const
{
	double c;
	double pai=3.1415926;
	c=4*pai*radius*radius;
	return c;
}
double CBall::Volume() const
{
	double c;
	double pai=3.1415926;
	c=pai*radius*radius*radius*4/3;
	return c;
}
class CCylinder : public CSolid
{
private:
		double radius;
	double height;
public:
	CCylinder(double r=0,double high=0);
	double SurfaceArea() const;
	double Volume() const;
};
CCylinder::CCylinder(double r,double high)
{
	radius=r;
	height=high;
}
double CCylinder::SurfaceArea() const
{
	double c;
	double pai=3.1415926;
	c=2*pai*radius*radius+2*pai*radius*height;
	return c;
}
double CCylinder::Volume() const
{
	double c;
	double pai=3.1415926;
	c=pai*radius*radius*height;
	return c;
}
int main( )
{
	CSolid *p;
	double s,v;

	CCube x(10);
	p=&x;
	s=p->SurfaceArea( );
	v=p->Volume( );
	cout<<"正方体边长为 10 "<<endl;
	cout<<"表面积："<<s<<endl;
	cout<<"体积："<<v<<endl;
	cout<<endl;

	CBall y(6.5);
	p=&y;
	s=p->SurfaceArea( );
	v=p->Volume( );
	cout<<"球体半径为  6.5"<<endl;
	cout<<"表面积："<<s<<endl;
	cout<<"体积："<<v<<endl;
	cout<<endl;

	CCylinder z(5,10);
	p=&z;
	s=p->SurfaceArea( );
	v=p->Volume( );
	cout<<"圆柱体底面半径、高分别为 5, 10"<<endl;
	cout<<"表面积："<<s<<endl;
	cout<<"体积："<<v<<endl;
	cout<<endl;
	return 0;
}

看着贺老师博客的方法写的      O∩_∩)O