c++多态（建立三个继承container的派生类cube、sphere 与cylinder）
#include<iostream>
using namespace std;
class container
{
public:
container(double radius1);
virtual double surface_area()=0;
virtual double volume()=0;
protected:
double radius;
};
container::container(double radius1)
{
radius=radius1;
}
class cube:public container
{
public:
cube(double radius1):container( radius1)
{
}
double surface_area()
{
return 6*radius*radius;
}
double volume()
{
return radius*radius*radius;
}
};
class sphere:public container
{
public:
sphere(double radius1):container( radius1)
{
}
double surface_area()
{
return 4*3.14*radius*radius;
}
double volume()
{
return 4/3*radius*radius*radius*3.14;
}
};
class cylinder:public container
{
public:
cylinder(double radius1,double h):container( radius1)
{
height=h;
}
double surface_area()
{
return 2*3.14*radius*radius+2*3.14*radius*height;
}
double volume()
{
return 3.14*radius*radius*height;
}
private:
double height;
};
int main()
{
container *x;
cube A(6.0);
x=&A;
cout<<"正方体的表面积是: "<<x->surface_area()<<endl;
//cout<<"正方体的表面积是: "<<A.surface_area()<<endl;
cout<<"正方体的体积是: "<<x->volume()<<endl;
// cout<<"正方体的体积是: "<<()<<endl;
sphere B(5.0);
x=&B;
cout<<"球体的表面积是: "<<x->surface_area()<<endl;
cout<<"球体的体积是: "<<x->volume()<<endl;
cylinder C(5.0,6.0);
x=&C;
cout<<"圆柱体的表面积是: "<<x->surface_area()<<endl;
cout<<"圆柱体的体积是: "<<x->volume()<<endl;
return 0;
}