helloworld

#include <iostream>using namespace std;class ClsBase{public:ClsBase(){ cout << "ClsBase constructor." << endl; }~ClsBase(){ cout << "ClsBase destructor." << endl; }};class ClsDerived : public ClsBase {public:ClsDerived(){ cout << "ClsDerived constructor." << endl; }~ClsDerived(){ cout << "ClsDerived destructor." << endl; }};int main(){ClsBase *p = new ClsDerived();delete p;return 0;}