C++ is strongly typed language. Your example is simple case of pointer arithmetic. "99" will be multiplied by number of bytes of size of type "x". To illustrate, here is an example:
int main()
{
int arri[10] = {0,1,2,3,4,5,6,7,8,9};
char arrc[10] = {'0','1','2','3','4','5','6','7','8','9'};
std::cout << "Int ptr:" << (&arri[0] + 1)[2] << "\n";
std::cout << "Char ptr:" << (&arrc[0] + 1)[2] << "\n";
return 0;
}