#include <cstdlib>
#include <iostream.h>

using namespace std;
class number2;
class number1
{
      private:
              int x;
      public:
             number1(){
                       x=5;
                       }
                       friend int sum(number1,number2);
                       };
class number2
 {
      private:
              int y;
      public:
             number2(){
                       y=20;
                       }
                       friend int sum (number1,number2);
                       };
      int sum(number1 ob1,number2 ob2)
      {
          return ob1.x+ob2.y;
      }
      

int main(int argc, char *argv[])
{
    number1 ob1;
number2 ob2;
cout<<"Sum of private data member"<<sum(ob1,ob2)<<endl;
    system("PAUSE");
    return EXIT_SUCCESS;
}