If a class may serve as a base class for others, its destructor should be virtual. This ensures RTTI support for objects of this class and objects derived from it, and more important, you ensure that the correct destructor is always called, even in the following case:
class Base{ char *p; Base() { p = new char [200]; } ~ Base () {delete [] p; } //... };class Derived : public Base { char *q; Derived() { q = new char[300]; } ~Derived() { delete [] q; } //...};void destroy (Base & b) { delete &b; }int main(){ Base *pb = new Derived(); //200 + 300 bytes have been allocated //... meddle with pb destroy (*pb); //Oops! Base
