Is `double` guaranteed by C++03 to represent small integers exactly?

Question

Does the C++03 standard guarantee that sufficiently small non-zero integers are represented exactly in double? If not, what about C++11? Note, I am not assuming

Answer 1

Well, 3.9.1 [basic.fundamental] paragraph 8 states

... The value representation of floating-point types is implementation-defined. ...

At least, the implementation has to define what representation it uses.

On the other hand, std::numeric_limits defines a couple of members which seem to imply that the representation is some in the form of significand radix ^exponent:

• std::numeric_limits::radix: the radix of the exponent
• std::numeric_limtis::digits: the number of radix digits

I think these statements imply that you can represent integers in the range of 0 ... radix ^digits - 1 exactly.