Thread: Singleton Class error

Code:

#include <iostream>

using namespace std;

class Myclass
{

	private:	
	static int count;
	
	
	Myclass()
	{

	}


	
	
	public:

	static Myclass* CreateInstance();

	~Myclass()
	{
		count--;

	}
};

 Myclass* Myclass::CreateInstance()
	{
		Myclass *ptr = NULL;		
		if(!count)
		{
			count++;
			ptr = new Myclass;
			return( ptr );
		}
		else
		{
			cout << "\nClass Instantiation no possible!\n";
			return NULL;
		}
	}


int main()
{
		Myclass *ob = Myclass :: CreateInstance();

		return 0;
}

ERROR MESSAGE..

Code:

/tmp/ccPSDOBz.o: In function `Myclass::CreateInstance()':
test.cpp:(.text+0x13): undefined reference to `Myclass::count'
test.cpp:(.text+0x1d): undefined reference to `Myclass::count'
test.cpp:(.text+0x26): undefined reference to `Myclass::count'
collect2: ld returned 1 exit status