Thread: static variables inside of a class.. possible?

Code:

#include <iostream.h>
#include <iomanip.h>
#include <stdlib.h>

using namespace std;

class Counter
    {
        private:
           static int serial;
           public:
                Counter():serial()
                    {inc_counter();}
                void show_serial()
                {
                    cout << "I am object number " << serial << endl;
                }
                void inc_counter()
                {
                    serial++;
                }
    };

int main()
{
    Counter s1, s2, s3;

    s1.show_serial();
    s2.show_serial();
    s3.show_serial();
    system("PAUSE");
    return 0;
}

basically, i want to be able to keep a "serial" number going inside of each object that will display a message saying "i am object number x" (x for whatever number)
the only way i know how to do this is by static, but its not working
any help with the code?

i wanna try to do everything within the class itself. i know i'd be easier if i passed it a number once its constructed, but eh
i think the quesiton is saying for everything to be inside the class

i also know somewhere in there i need to initilize it to 0
but static int serial =0 doesnt work

this is my first work with classes ever