const int ci = 3;                       // cv-qualified (initialized as required)
ci = 4;                                 // ill-formed: attempt to modify const

int i = 2;                              // not cv-qualified
const int* cip;                         // pointer to const int
cip = &i;                               // OK: cv-qualified access path to unqualified
*cip = 4;                               // ill-formed: attempt to modify through ptr to const

int* ip;
ip = const_cast<int*>(cip);             // cast needed to convert const int* to int*
*ip = 4;                                // defined: *ip points to i, a non-const object

const int* ciq = new const int (3);     // initialized as required
int* iq = const_cast<int*>(ciq);        // cast required
*iq = 4;                                // undefined: modifies a const object