it can help you use C++ program we

				//测试a.h中定义的类
				#include 
				#include "a.h"
				using namespace std;
				
				void foo( A* obj)
				{
					obj->Display();
				}
				
				int main()
				{
					A	a;
					B	b;
					C	c;
					foo( &a );
					foo( &b );
					foo( &c );
				
					return 0;
				}