On 3/19/06, Shriramana Sharma <samjnaa@xxxxxxxxx> wrote: > I did not get what is intended to be conveyed by: > > http://charm.cs.uiuc.edu/users/olawlor/ref/examples/cpp/virtual.cpp > http://charm.cs.uiuc.edu/users/olawlor/ref/examples/cpp/virtual_destructor.cpp 1. In C++ the virtual keyword identifies to the compiler that a class function may be overridden in a derived class. That is, the derived class may supply a function of the same name and argument list, but with different functionality defined in the function body. In the example you linked to the child class has overriden the virtual function hello and allows itself to be overridden by declaring its function virtual as well. A pointer to a derived class object may be assigned to a base class pointer, and a virtual function called through the pointer. If the function is virtual and occurs both in the base class and in derived classes, then the right function will be picked up based on what the base class pointer "really" points at. 2. Virtual destructors are needed to allow for the destructors for the actual object types derived from the base class to be called. Non virtual destructors in base classes can result in memory leaks. \Steve - : send the line "unsubscribe linux-c-programming" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
