int main()
{
    const int a = 1;

    // no problem assigning the value of a const variable to a non-const variable
    int b = a;

    // equivalent types
    const int* c = &a; 

    // const cast must be used to assign (pointer to const) => (pointer)
    int* d = const_cast<int*>(c);

    // no cast required to assign (pointer) => (pointer to const)
    const int* e = d;

    // no cast required to go from (pointer) => (const pointer)
    int* const f = d;

    // no cast required to go from (const pointer) => (pointer)
    // this is just assigning the value of a non-changable pointer
    int* g = f;

    // equivalent types
    int const ** h = &c;

    // equivalent types
    int*const* i = &f;

    // initialize constant pointer to pointer to int
    int**const j = &d; 

    // const cast required to go from (pointer to const pointer) => (pointer to pointer)
    int** k = const_cast<int**>(i);

    // no cast required to go rom (pointer to pointer) => (const pointer to const pointer to const)
    int const *const*const m = k;

    return 0;
}