Why constructers can not be inherrited in c plus plus?

Answer 1

Every class of object must provide its own specific construction code. Since they are not really functions they cannot be overridden, thus they cannot be inherited. The same applies to the class destructor and the class self-assignment operator. Each class must handle these explicitly, within the class implementation. They cannot be implemented outside of the class, and therefore cannot be inherited.

Although the virtual keyword can be applied to the destructor, it's not a function and therefore not a virtual function. The only reason for having a virtual destructor at all is when one or more of the class methods are virtual. Since classes with virtual methods are intended to act as generic interfaces for more specialised implementations, it's important that when destroying such a class that the most-derived (or most-specialised) class is destroyed first, working up the hierarchy to the base class which must always be destroyed last. This can only be achieved through virtual destruction. Failure to declare the base class destructor virtual could result in a base class being destroyed (such as when deleting a pointer to it), which would then result in an incomplete and therefore invalid derived class remaining in memory.