#include using namespace std; class base { protected: string m_FirstName; public: base() : m_FirstName("Ketan") { cout << "base ctor\n"; } virtual ~base() { cout << "base dtor\n"; } virtual void display() { cout << " base display " << m_FirstName << " \n"; } }; class derived : public base { protected: string m_LastName; public: derived() : m_LastName("Lalcheta") { cout << "derived ctor\n"; } ~derived() { cout << "derived dtor\n"; } virtual void display() { cout << " derived display " << m_FirstName << " " << m_LastName << " \n"; } virtual void display1() { cout << " derived1 display " << m_FirstName << " " << m_LastName << " \n"; } }; //Normal case, own object by pointer void Test1() { base* pb = new base; derived* pd = new derived; pb->display(); pd->display(); delete pb; delete pd; } ////upcasting, no extra effort as we do have implicit convsersion void Test2() { base* pb = new derived; pb->display(); delete pb; } //upcasting, explicit conversion with static_cast void Test3() { base* pb = static_cast(new derived); pb->display(); delete pb; } //downcasting, explicit conversion with static_cast void Test4() { //base holding derived class object { base* pb = static_cast(new derived); pb->display(); derived* pd = static_cast(pb); if (pd) { cout << " " << pb << " and " << pd << endl; pd->display(); } else cout << "Could not cast\n"; delete pb; } cout << endl << endl << endl; //base holding base class object { base* pb = static_cast(new base); pb->display(); derived* pd = static_cast(pb); if (pd) { cout << " " << pb << " and " << pd << endl; pd->display(); //pd->display1();// This throws error and hence we should be doing dynamic cast instead of static_cast } else cout << "Could not cast\n"; delete pb; } } //downcasting, explicit conversion with dynamic_cast void Test5() { //base holding derived class object { base* pb = static_cast(new derived); pb->display(); derived* pd = dynamic_cast(pb); if (pd) { cout << " " << pb << " and " << pd << endl; pd->display(); } else cout << "Could not cast\n"; delete pb; } cout << endl << endl << endl; //base holding base class object { base* pb = static_cast(new base); pb->display(); derived* pd = dynamic_cast(pb); if (pd) { cout << " " << pb << " and " << pd << endl; pd->display(); } else cout << "Could not cast\n"; delete pb; } } int main() { //Normal case, own object by pointer //Test1(); //cout << "------------------------------------------------------------------\n"; //upcasting, no extra effort as we do have implicit convsersion //Test2(); //cout << "------------------------------------------------------------------\n"; //upcasting, explicit conversion with static_cast //Test3(); //cout << "------------------------------------------------------------------\n"; //downcasting, explicit conversion with static_cast Test4(); //cout << "------------------------------------------------------------------\n"; //downcasting, explicit conversion with dynamic_cast //Test5(); return 0; }

Static Vs Dynamic Cast