#include <iostream.h>
class A{
public：
virtual void printMe(){cout<<"This is class A printing. "<<endl；}；
} ；
class B：public A{
public：
void printMe() {cout << "This is class B printing. "<<endl；}
} ；
class C：public B{
public：
void printMe() {cout <<"This is class C printing. "<<endl；}
} ；
void print(A a)
{
a.printMe()；
}
void main()
{
B b；
C c；
print(b)；print(c)；
}
THIS IS CLASS A PRINTING.
THIS IS CLASS A PRINTING.
