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

Do you necessarily want the smallest, as opposed to using int for types smaller than int?

If not, and your compiler supports it, could you do:

int main()
{
    typeof('A') i_65 = 0; // declare variable 'i_65' of type 'char'
    typeof(10) i_10 = 0; // int
    typeof(10000) i_10000 = 0; // int
    typeof(1000000000000LL) i_1000000000000 = 0; // int 64
}