poly1.cpp

template <class Impl>
class Base {
public:
    static int DoWork() {
        return Impl::DoSubWork();
    }
};

class WorkA : public Base<WorkA> {
public:
    static int DoSubWork() {
        return 1;
    }
};

class WorkB : public Base<WorkB> {
public:
    static int DoSubWork() {
        return 2;
    }
};

int main() {
    WorkA::DoWork();
    WorkB::DoWork();
    return 0;
}

poly2.cpp

template<class Work>
int DoWork() {
    return Work::DoSubWork();
}

class WorkA {
public:
    static int DoSubWork() {
        return 1;
    }
};

class WorkB {
public:
    static int DoSubWork() {
        return 2;
    }
};

int main() {
    DoWork<WorkA>();
    DoWork<WorkB>();
    return 0;
}

poly3.cpp

class Base {
public:
    virtual int DoSubWork() = 0;

    int DoWork() {
        return DoSubWork();
    }
};

class WorkA : public Base {
public:
    virtual int DoSubWork() {
        return 1;
    }
};

class WorkB : public Base {
public:
    virtual int DoSubWork() {
        return 2;
    }
};

int main() {
    WorkA().DoWork();
    WorkB().DoWork();
    return 0;
}