#include <iostream>
using std::cout;
using std::endl;

struct base
{
    virtual void test() = 0;
};

class derived : public base
{
    void test()
    {
        cout << "private function... can not be called externally" << endl;
    }
};

int main(int argc, char* argv[])
{
    base* bs = new derived; 

    // call a private function, priave is not checked at runtime
    bs->test();

    return 0;
}