#include < iostream.h>
class XY {
   protected:
      int x, y;
   public:
      XY(int X, int Y) { x = X; y = Y; }
      int getX() { return x; }
      int getY() { return y; }
};

class XYZ : public XY {
   protected:
      int z;
   public:
      // derived class constructors
      XYZ(int X, int Y, int Z) : XY(X, Y)
      { z = Z; }
      int getZ() { return z; }
};

void main()
{
   XYZ point1(10,20,30);
   cout << "x: " << point1.getX() << endl;
   cout << "y: " << point1.getY() << endl;
   cout << "z: " << point1.getZ() << endl;
}