C++ static class member field data

#include <iostream>
using namespace std;
class foo/*  w w w.  ja  v  a2 s  . c o  m*/
{
   private:
       static int count;   //only one data item for all objects
       //note: *declaration* only!
   public:
       foo()               //increments count when object created
       { count++; }
       int getcount()      //returns count
       { return count; }
};
int foo::count = 0;       //*definition* of count
int main()
{
   foo f1, f2, f3;        //create three objects
   cout << "count is " << f1.getcount() << endl;  //each object
   cout << "count is " << f2.getcount() << endl;  //sees the
   cout << "count is " << f3.getcount() << endl;  //same value
   return 0;
}