Constructor does not support virtual functions because we need an object to invoke a virtual method in the first place and more over constructors are used to initializing objects,which is a static type.Virtual functions are invoked on the dynamic type of the object,hence the object may not be properly initialized when a constructor call is made.Since the derived part of the object would not be initialized during the execution of base class constructor,hence calling any virtual method from base class constructor does not work well.