第13周项目3立体类族共有的抽象类

#include <iostream>

using namespace std;
const double pai=3.14;
class CSolid
{
public:
virtual double area()=0;
virtual double volume()=0;
} ;
class CCube:public CSolid
{
public:
CCube(double x=0);
double area();
double volume();
private:
double length;
};
CCube::CCube(double x)
{
length=x;
}
double CCube::area()
{
return 6*length*length;
}
double CCube::volume()
{
return length*length*length;
}
class CBall:public CSolid
{
private:
double radius;            // 圆周率
public:
CBall(double r=0);
double area(); // 求表面积
double volume();    // 求体积;
};
CBall::CBall(double r)
{
radius=r;
}
double CBall::area()
{
return 4*pai*radius*radius;
}
double CBall::volume()
{
return pai*radius*radius*radius*4/3;
}
class CCylinder:public CSolid
{
public:
CCylinder(double r=0,double h=0);
double area(); // 求表面积
double volume();    // 求体积;
private:
double radius,height;
};
CCylinder::CCylinder(double r,double high)
{
radius=r;
height=high;
}
double CCylinder::area()
{
double c;
c=2*pai*radius*radius+2*pai*radius*height;
return c;
}
double CCylinder::volume()
{
double c;
c=pai*radius*radius*height;
return c;
}

int main( )
{
CSolid *p;
double s,v;
CCube x(3);
cout<<"立方体边长为 3 "<<endl;
p=&x;
s=p->area( );
v=p->volume( );
cout<<"表面积："<<s<<endl;
cout<<"体积："<<v<<endl;
cout<<endl;
CBall y(4.0);
cout<<"球体半径为 4.0 "<<endl;
p=&y;
s=p->area( );
v=p->volume( );
cout<<"表面积："<<s<<endl;
cout<<"体积："<<v<<endl;
cout<<endl;
CCylinder z(10,20);
cout<<"圆柱体底面半径、高分别为 10, 20"<<endl;
p=&z;
s=p->area( );
v=p->volume( );
cout<<"表面积："<<s<<endl;
cout<<"体积："<<v<<endl;
cout<<endl;
return 0;
}