第六章

#include <iostream>
using namespace std;

const double PI=3.1415927;

class Base {
public:
 Base(double x):h(x)
 {

 }
 virtual void disp()=0;
protected:
 double h;//高
};

class Cuboid:public Base{
public:
 Cuboid(double x=0, double y=0, double z=0):Base(z),c(x), k(y)
 {

 }
 virtual void disp()
 {
  cout <<"长方体体积 " << c*k*h << endl;
 }
private:
 double c,k;// 长,宽
};

class Cylinder:public Base{
public:
 Cylinder(double a=0, double b=0):Base(b), r(a)
 {

 }
 virtual void disp()
 {
  cout << "圆柱体体积 " << h*PI*r*r<< endl;
 }
private:
 double r;//底半径
};
int main() {
 Cuboid a(1,2,3);
 Cylinder b(1,2);

 Base *pc = &a;
 pc->disp();
 pc = &b;
 pc->disp();

return 0;
}