1. To distinguish the declaration of the postfix operators from the declaration of the prefix operators, the declarations for the overloaded increment and decrement postfix operators have an extra parameter of type int. 
    class ScreenPtr {
public:
   // prefix operators
   Screen& operator++();
   Screen& operator--();
   // postfix operators
   Screen& operator++(int);
   Screen& operator--(int);
};

#include <iostream>
#include <string>


class Screen {
public:
   Screen(int x, int y) : m_x(x), m_y(y){};
private:
   int m_x;
   int m_y;
};

class ScreenPtr{
public:
   ScreenPtr( Screen& s, size_t arraySize = 0)
           : m_ptr(&s), m_size(arraySize), m_offset(0){};

   // prefix operators
   Screen& operator++();
   Screen& operator--();
   // postfix operators
   Screen& operator++(int);
   Screen& operator--(int);
private:
   Screen* m_ptr;
   size_t m_size;
   size_t m_offset;
};

Screen& ScreenPtr::operator++()
{
   if ( m_size == 0 ){
      std::cout << "Cannot increment pointer to single object" << std::endl;
      return *m_ptr;
   }

   if ( m_size == m_offset ){
      std::cout << "Already one past the end of the array" << std::endl;
      return *m_ptr;
   }
   ++m_offset;
   return *++m_ptr;
}

Screen& ScreenPtr::operator++(int)
{
   if ( m_size == 0 ){
      std::cout << "Cannot increment pointer to single object" << std::endl;
      return *m_ptr;
   }

   if ( m_size == m_offset ){
      std::cout << "Already one past the end of the array" << std::endl;
      return *m_ptr;
   }
   ++m_offset;
   return *m_ptr++;
}

int main(){
   Screen s(5, 6);
   ScreenPtr sptr(s);
   return 0;
}