How to initialize static base type to a derived type?

[wolfv]

Is there a way to do this?:
Base classes are in a library that the user can not edit.
The library has a class containing a static variable; the static variable is a base type object.
The user derives a class from the base class and initialize the static variable to a user derived type object.

Here is a simplified example of what I am trying to do:

#include <iostream>

class numBase				//numBase is in a library user can not edit
{
};

class numDer : public numBase		//user defined class
{
	private:
		int num;
	public:
		void printNum() { std::cout << " numDer=" << num; }
		void inc() { num++; }
};

class containerBase			//containerBase is in a library user can not edit
{
	protected:
		static numDer count;	//this compiles, but user can not initilize count to other types
		//static numBase count;	//this causes error on line 26
};

class containerDerived : public containerBase //user defined class
{
	public:
		void inc() { count.inc(); } //error: 'class numBase' has no member named 'inc'
		void printCount() { std::cout << " containerDerived"; count.printNum(); }
};

/************************ user program **********************/
//initilialize static variable
numDer number;				//number could be any user defined type derived from numBase
numDer containerBase::count = number;	//initialize count to user defined type

int main()
{
	containerDerived container1;
	containerDerived container2;

	container1.printCount();
	container1.inc();
	container2.inc();
	container1.printCount();

output:

 containerDerived numDer=0 containerDerived numDer=2

Thank you.

[Aceix]

If it was possible to static count, then using it in the derived class would be meaningless. Because, what is the guarantee that the static member is initialized.

Aceix.

[wolfv]

Hi Aceix.

The compiler would check line 20 (if it were uncommented) to see if static count was initialize to a kind of numbBase, which it is on line 33.
That would guarantee that the static member is initialized.

How is using static count in the derived class would be meaningless?