#include #include using namespace std; // ---------------------------------------- // materials // The Material class must NOT be template class // only its method "send" have to be template. // We CAN'T remove the template type. class Material { public: template void send(const T& v) { // should be virtual, pure if possible cout << "Sending from Material (parent)" << endl; } }; class PhongMaterial : public Material { public: template void send(const T& v) { // should be printing this one and not the parent cout << "Sending from PhongMaterial (child)" << endl; } }; // ---------------------------------------- // with reference class Actor_A { public: Actor_A(const Material& material) { m_material = material; } void render() { m_material.send(1); } protected: Material m_material; // Contains a Material (a derived Material) }; class Cube_A : public Actor_A { public: Cube_A(): Actor_A(PhongMaterial()) {} // < creating PhongMaterial here }; // ---------------------------------------- // with pointers class Actor_B { public: Actor_B(Material* material) { m_material = material; } void render() { m_material->send(1.0f); } protected: Material* m_material; // Contains a Material (a derived Material) }; class Cube_B : public Actor_B { public: Cube_B(): Actor_B(new PhongMaterial()) {} // < creating PhongMaterial here }; // ---------------------------------------- int main() { Cube_A cubeA; Cube_B cubeB; cubeA.render(); // should be printing the PhongMaterial sentence cubeB.render(); // should be printing the PhongMaterial sentence return 0; }

c++ derived class - virtual template method