#include<iostream>
using namespace std;

class Bus{
   public:
       void print();
};

void test();

class Truck{
  private:
      int x;
  protected:
    int y;
  public:
    int z;
   
   friend class Bus;
    /*friend void Bus::print();
    friend void test();*/
};

void test(){
   /// access the private Truck
   Truck t;
   t.x = 10;
   t.y = 20;
   cout<<t.x<<" "<<t.y<<endl;
}

void Bus::print(){
   Truck t;
   t.x = 10;
   t.y = 20;
   cout<<t.x<<" "<<t.y<<endl;
}

int main(){
   Bus b;
   b.print();
    
    test();
  return 0;
}