class CTestA
{
    public:
        virtual void TestFunction(int value) = 0;
};

class CTestB : public CTestA
{
    public:
        virtual void TestFunction(int value) {}
};

class CTestC : public CTestB
{
    public:
        virtual void TestFunction(const char * c_szValue) {}
};

int _tmain(int argc, _TCHAR* argv[])
{
    CTestC testC;
    CTestA * pTest = &testC;

    pTest->TestFunction(1);        // !!

    return 0;
}

class CTestC : public CTestB
{
    public:
        virtual void TestFunction(const char * c_szValue) override {}
        // error C3668: 'CTestC::TestFunction' : method with override
        // specifier 'override' did not override any base class methods
};