see these sample:
Code:
#include <iostream>

using namespace std;


class test
{
    public:
     virtual void hey()
     {
         cout << "hello world!!!\n";
     }
};


class test2: public test
{


}test2;


void test2::hey()
{
    cout << "hey brother\n";
}
the 'hey' is declared on 'test'.. if the 'test2' is from 'test', why i must re-declare the 'hey' function?
(i mean i must change the 'test' functions, on a derive class without re-declare them)