#include <iostream>class Foo{public:  void func1()   {      std::cout << "1- Foo" << std::endl;   }  virtual void func2()  {     std::cout << "2- Foo" << std::endl;  }  virtual ~Foo()   {    // The class needs a virtual destructor so that     // delete destroys the object based on its    // dynamic type (matching the call to new) and    // not based on the static type of the pointer    // holding the object (which falls into 'undefined    // behaviour' - silently generates invalid code).  }};class Bar : public Foo{public:  void func1()   {      std::cout << "1- Bar" << std::endl;   }  virtual void func2()  {     std::cout << "2- Bar" << std::endl;  }  // base Foo's destructor is virtual, so will be Bar's};int main(){   Foo* a = new Foo; // static type - Foo, dynamic type - Foo   Foo* b = new Bar; // static type - Foo, dynamic type - Bar   Bar* c = new Bar; // static type - Bar, dynamic type - Bar   std::cout << "1- is non virtual - uses the type of the pointer" << std::endl;   std::cout << "2- is virtual - uses the type of the object" << std::endl;   a->func1(); // prints "1- Foo" - the pointer is a Foo*   a->func2(); // prints "2- Foo" - the object is a Foo   b->func1(); // prints "1- Foo" - the pointer is a Foo*   b->func2(); // prints "2- Bar" - the object is a Bar   c->func1(); // prints "1- Bar" - the pointer is a Bar*   c->func2(); // prints "2- Bar" - the object is a Bar   delete a; // destructor is virtual, delete a Foo, ok   delete b; // destructor is virtual, delete a Bar, ok   delete c; // destructor is virtual, delete a Bar, ok};[/quote]