Automatically pick a variable type big enough to hold a specified number

Question

Is there any way in C++ define a type that is big enough to hold at most a specific number, presumably using some clever template code. For example I want to be able to writ

Answer 1

#define UINT8_T   256
#define UINT16_T  65536
#define UINT32_T  4294967296

template
struct UInt16_t { typedef uint16_t type; };
template
struct UInt16_t { typedef uint32_t type; };

template
struct UInt8_t { typedef uint8_t type; };
template
struct UInt8_t { typedef typename UInt16_t::type type; };

template
struct Integer {
  typedef typename UInt8_t::type type;
};

You can extend upto uint64_t or whatever your platform supports.

Demo.