// Copyleft: Sathiamoorthy Manoharan.

#include <iostream>

int
main()
{
   const int MYMAX = 16;
   int array[MYMAX];
   for ( int i = 0; i < MYMAX; ++i )
   {
      array[i] = i*i;
   }

   std::cout << "index\tvalue\taddress\n";
   for ( int i = 0; i < MYMAX; ++i )
   {
      std::cout << i << "\t" << array[i]  << "\t" 
                << (unsigned long) &array[i] << "\n";
   }

   // Now we change the last element of the array 
   // by picking the address of the last element of the array
   // and changing the content the address is pointing to.
   // This is equivalent to saying array[MYMAX-1] = 3737599
   int* lastAddress =  &array[MYMAX-1];
   *lastAddress = 3737599;

   std::cout << "modified array:\n";
   for ( int i = 0; i < MYMAX; ++i )
   {
      std::cout << i << "\t" << array[i]  << "\t" 
                << (unsigned long) &array[i] << "\n";
   }

   // Now we change the last element of the array again.
   // We compute the address of the last element of the array
   // from the address of the first element and the last element's
   // offset from the first element.
   // We then change the content the last address is pointing to.
   // This is equivalent to saying array[MYMAX-1] = 3737000
   int* firstAddress =  &array[0];
   int* lastAddress2 = firstAddress + (MYMAX - 1);
   *lastAddress2 = 3737000;

   std::cout << "modified array:\n";
   for ( int i = 0; i < MYMAX; ++i )
   {
      std::cout << i << "\t" << array[i]  << "\t" 
                << (unsigned long) &array[i] << "\n";
   }

   // In C/C++, the name of an array is in fact the address of the
   // first element of the array. Thus, '&array[0]' is equivalent
   // to 'array'. So we replace 'firstAddress' (i.e. &array[0]) by
   // simply 'array' here to compute the last address.
   int* lastAddress3 = array + (MYMAX - 1);
   *lastAddress3 = 2778000;

   std::cout << "modified array:\n";
   for ( int i = 0; i < MYMAX; ++i )
   {
      std::cout << i << "\t" << array[i]  << "\t" 
                << (unsigned long) &array[i] << "\n";
   }

   return 0;
}