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

How about a conditional:

#include 
#include 

template 
struct MinInt
{
  typedef typename std::conditional< N < std::numeric_limits::max(),
       unsigned char, std::conditional< N < std::numeric_limits::max(),
         unsigned short int>::type,
         void*>::type>::type
    type;
};

This would have to be extended to encompass all desired types, in order; at the final stage you could use enable_if rather than conditional to have an instantiation error right there if the value is too large.