LNK2020: unresolved token (0A00000B)

I'm new in C++, i'm using windows forms. i have done a class in the stdafx.h file like this:

class bookings{
public:
bookings(){};
static int floor;
static void setFloor(int f) { floor = f; }
static int getFloor() { return floor; }
//static int roomType;
//static char* client[30];
};

then in the form1.h i'm try

bookings::setFloor(1);

Then, the error appears. Please help!

why write it in stdafx.h? is stdafx inlcuded in form1.h? Why are you writing implementation code in a header - it normally goes in the .cpp file.