#include <iostream>
using namespace std;

int main()
{
   int * ptr;			// a pointer

   cout << "The value of ptr = " << ptr << '\n';
   cout << "Now initializing ptr to null pointer\n";

   ptr = 0;

   cout << "The value of ptr = " << ptr << '\n';

   if (ptr == 0)
     cout << "Pointer unsafe to de-reference\n";
   else
     cout << "Pointer safe to de-reference\n";

   cout << "Attempting to dereference ptr\n";
   cout << "*ptr = " << *ptr << '\n';

   return 0;
}