#include <iostream>

using namespace std;

int main() {
  volatile const int j = 0;
  const volatile int k = 1;

//This is the correct answer.  As strange as it may seem, it is possible for a variable to be const and volatile at the same time.  This essentially means that the variable cannot be changed by the programmer through C++ code, but it can be changed behind your back by something outside the program's control (an external device, for example).

//const int const * j = 0;
//This is incorrect.  The declaration may appear to be a const pointer to a const int.  However, it is actually an invalid declaration because the second const in on the wrong side of the asterisk "*".
 
//const int j;
//This is incorrect.  A const variable must be initialized.  Note that in C, this declaration would be possible if it were for a global variable because const variables are extern by default, which means they could be defined (and initialized) somewhere else..  However, in C++, such a declaration is never valid since const variables are static by default.
 
//void* j, k;
//aThis is incorrect.  Despite appearances, the second variable, k, is not declared to be a "void*."  It is actually declared to be a void. It is not possible to have a variable of type void (you cannot have a variable with no type).

  int *l = const_cast<int*>(&k);
  *l = 10;
  cout << "k = " << k << endl;

  return 0;
}